bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Clq, Cls and Cl̄ Inh synthesized by stimulated human monocytes in vitro
Authors: Reboul Angeline , Prandini Marie-Hélène , Bensa Jean-Claude , Colomb Maurice G.
Published: July 2002

Clq, Cls and Cl̄ Inh synthesized and secreted by human monocytes were characterized by SDS‐PAGE. Clq is formed of three chains A (M
r ~35000), B (M
r ~33000) and C (M
r ~25000) which are associated in two subunits A‐B and C‐C. It appears identical to C1q purified from plasma. Cls is secreted as a non‐activated, monocatenar protein of M
r ~87000 identical to proenzymic Cls from plasma. Secreted Cl̄ Inh (M
r ~100000) has a slightly higher M
r than purified plasmatic Cl̄ Inh. Monensin treatment of the cells favours the intracytoplasmic accumulation of products at various glycosylation stages.
Isolation of gram quantities of isoleucyl‐tRNA synthetase from an overproducing strain of Escherichia coli and its use for purification of cognate tRNA
Authors: Kawakami Makoto , Miyazaki Masazumi , Yamada Hisami , Mizushima Shoji
Published: July 2002

The ileS gene coding for isoleucyl‐tRNA synthetase was cloned on a runaway‐replication plasmid. From the cells harboring the plasmid, gram quantities of the synthetase were isolated using two column procedures. The synthetase was used for the purification of cognate tRNA. Isoleucine tRNAGAU of greater than 90% purity was easily isolated by taking advantage of a specific complex formation of the synthetase with cognate tRNA.
Selective oxidative destruction of iron‐sulfur clusters
Authors: Morgan T.V. , Stephens P.J. , Devlin F. , Burgess B.K. , Stout C.D.
Published: July 2002

The destructive oxidation of aerobically isolated 7Fe Azotobacter vinelandii ferredoxin I [(7Fe)FdI] by Fe(CN)6
3− is examined using low‐temperature magnetic circular dichroism (MCD) and EPR. The results demonstrate that oxidation of the [3Fe‐3S] cluster occurs only after essentially complete destruction of the [4Fe‐4S] cluster. It is therefore feasible by controlled Fe(CN)6
3− oxidation to obtain a partially metallated form of FdI, (3Fe)FdI, containing only a [3Fe‐3S) cluster. The MCD and EPR data demonstrate that the [3Fe‐3S] cluster in (3Fe)FdI is essentially identical in structure to that in the native protein.
Identification in several human myeloid leukemias or cell lines of a DNA rearrangement next to the c‐mos 3́‐end
Authors: Revoltella Roberto P. , Park Morag , Fruscalzo Alberto
Published: July 2002

Proto‐oncogene
c‐mos
DNA rearrangement
Myeloid leukemia
Evidence of hemin as an end product inhibitor of L‐alanine:4,5‐dioxovalerate transaminase in rat liver mitochondria
Authors: Shanker J. , Datta K.
Published: July 2002

L‐Alanine: 4,5‐dioxovalerate transaminase
Heme biosynthesis
Hemin
End product inhibitor
Amino acid sequence alignment of cereal storage proteins
Authors: Reeck Gerald R. , Hedgcoth Charles
Published: July 2002

An alignment is presented of portions of the amino acid sequences of two gliadins and a glutenin from wheat and of a barley hordein. The two gliadins exhibit similarity over much of their sequences. The glutenin is similar in sequence to the gliadins only over a restricted region. Our analysis of the aligned sequences leads us to suggest the word ‘modular’ to describe the architecture of these proteins. The term is intended to connote the joining together, in the course of evolution, of several units (modules) of distinctive character, under a set of rules that allows considerable flexibility in the arrangement of modules within a molecule.
Cationic amphiphilic drugs inhibit the synthesis of long‐chain fatty acyl coenzyme A in rat brain microsomes
Authors: Reddy T.Sanjeeva , Bazan Nicolas G.
Published: July 2002

Propranolol
Tetracaine
Chloroquine
Arachidonic acid
Docosahexanoic acid
Long‐chain acyl coenzyme A synthetase
Local anesthetic
A metabolic switch produced by enzymically interconvertible forms of an enzyme
Authors: Crabtree B.
Published: July 2002

A system of enzymically interconvertible enzyme forms (interconversion cycle) is known to increase the sensitivity to regulators. Here it is shown that this system may also provide a discrete switching mechanism in which the response is maintained when the stimulus is removed. These switches may be important in producing discontinuous metabolic changes such as those associated with cell differentiation.
The inhibition of mitochondrial F1‐ATPase by 1,5‐difluoro‐2,4‐dinitrobenzene
Authors: Akhrem A.A. , Kisel M.A. , Kozlov I.A. , Tsybovsky I.S. , Vulfson E.N.
Published: July 2002

1,5‐Difluoro‐2,4‐dinitrobenzene completely inhibits F1‐ATPase when it is used at micromolar concentrations and the inhibitor/enzyme molar ratio is equal to 3. The inhibition can be reversed by dithiothreitol treatment. 7‐Chloro‐4‐nitrobenzofurazan treatment of F1‐ATPase does not prevent the reaction of the enzyme with 1,5‐difluoro‐2,4‐dinitrobenzene. The 1,5‐difluoro‐2,4‐dinitrobenzene‐induced inhibition is thought to be a result of the modification of a tyrosine residue with pK 9.1.
Designed inhibitors of horse liver alcohol dehydrogenase
Authors: Freudenreich Charles , Pfangert Ursula , Weis Marianne , Zeppezauer Michael , Biellmann Jean-François
Published: July 2002

3‐(p‐Butoxyphenyl)propionamide, ‐thioamide and ‐hydrazide and the formamide of p‐butoxybenzylamine were tested as inhibitors of cadmium(II) and cobalt(II) active‐site substituted alcohol dehydrogenase. The results agree with a direct coordination of these inhibitors except for the hydrazide to the active‐site metal ion, in the enzyme‐NADH‐inhibitor complex. The hydrazide might be situated at some distance from the metal ion without a direct coordination bond.
Accumulation of exoglucanase activity in yeast secretory mutants blocked at the endoplasmic reticulum level
Authors: Hernández Luis M. , Olivero Isabel , Ramírez Manuel , Larriba Germán
Published: July 2002

Saccharomyces cerevisiae HMSF‐176 (sec 18), a thermosensitive secretory mutant blocked at the endoplasmic reticulum (ER) level, drastically increased its osmotic sensitivity when grown at the restrictive temperature of 37°C in high glucose concentration. This fact led to the erroneous interpretation that glucanases were inactive when localized in the ER. The development of a suitable osmotic stabilizer now indicates that sec 18 accumulates exoglucanase activity. Another ER‐blocked mutant behaved in a similar way. All the accumulated exoglucanase was found in a soluble form. By contrast, a significant portion of the accumulated invertase remained in a membrane‐bound form.
Biochemical properties of macrophage fractions and their relation to the mechanism of Superoxide production
Authors: Diamond Michael S. , Holian Andrij
Published: July 2002

Guinea pig alveolar macrophages are separable by density gradient centrifugation into three subpopulations whose capacity for biological activity (e.g. O2
−production and chemotaxis) varies directly with buoyant density [(1983) J. Reticuloendothel. Soc. 33, 157‐164]. This study demonstrates that the activity per cell of various other enzymes remains constant among the subpopulations. When normalized for cell volume, enzyme activity diminishes with decreasing buoyant density. Intracellular calcium mobilization, linked to formyl peptide and concanavalin A‐stimulated O2
− production, similarly diminishes. Formyl peptide receptor distribution and affinity remain constant. Decreased responsiveness of lower density cells is probably due to lower concentration of enzyme(s) involved in the transduction of signal distal to ligand recognition (or binding).
B‐ring of colchicine and its role in taxol‐induced tubulin polymerization
Authors: Ghosh Choudhury Goutam , Maity Sankar , Bhattacharyya Bhabatarak , Biswas Birendra B.
Published: July 2002

Taxol‐induced assembly of purified tubulin is not inhibited by the colchicine analogue 2‐methoxy‐5‐(2',3',4'‐trimethoxyphenyl)tropone. Colchicine analogues having intact A, C and B‐rings (without NH‐CO‐CH3) such as desacetamidocolchicine have also been found to be inactive. It has been observed that these two colchicine analogues are incorporated into polymers when incubated in the presence of taxol. Furthermore, preformed taxol‐induced polymers of tubulin have been found to bind these two colchicine analogues. These results suggest that colchicine‐binding domains on the tubulin molecule are mostly (if not completely) exposed in the taxol‐induced polymers.
The structure around the thioester bond in bovine α2‐macroglobulin
Authors: Björk Ingemar , Jörnvall Hans
Published: July 2002

The residues contributing to the thioester bonds in bovine α2‐macroglobulin were differentially labelled by modification of the Glu moiety with [14C]methylamine and of the Cys moiety with iodo[3H]acetate. The labelled region was identified and analyzed in a tryptic peptide. Two amino acid replacements between human and bovine α2‐macroglobulin were found at positions + 3 (Val/Ala) and + 4 (Leu/Arg) from the Glu moiety of the thioester. Thus, marked differences exist between the human and bovine proteins in side chain size and charge close to the thioester bonds. These differences may explain the greater conformational stability of bovine α2‐macroglobulin, compared with that of the human inhibitor, after cleavage of the thioester bonds.
A tentative model of formation of structural proteins of tick‐borne encephalitis virus (flavivirus)
Authors: Lyapustin V.N. , Svitkin Yu.V. , Ugarova T.Yu. , Lashkevich V.A. , Agol V.I.
Published: July 2002

The time course of tick‐borne encephalitis virus cell‐free protein synthesis was studied by using either [35S]‐methionine or formyl[35S]methionyl‐tRNAf
Met as substrates, and the [35S]methionine‐labelled products were compared by fingerprinting tryptic peptides. An intermediate in the protein processing, the polypeptide doublet p, was characterized and a tentative model for flavivirus structural protein synthesis and processing was proposed.
Purification of a cytolytic factor from purple fluid of a sea hare
Authors: Yamazaki Masatoshi , Kimura Katsuya , Kisugi Jun , Kamiya Hisao
Published: July 2002

A cytolytic factor inducing tumor lysis was purified approx. 1000‐fold from purple fluid of the sea hare Aplysia kurodai. The purified factor appeared homogeneous on polyacrylamide gel electrophoresis and consisted of a single polypeptide chain of 60 kDa. The cytolytic factor was half‐maximally active at 3–25 ng protein/ml and lysed all tumor cells tested, but not normal cells.
Fe‐dependent formation of a protein that makes mitochondria lipoxygenase‐susceptible during maturation of reticulocytes
Authors: Rapoport S. , Schmidt J. , Prehn S.
Published: July 2002

During in vitro incubation the mitochondria of immature reticulocytes fail to be degraded by lipoxygenase and subsequent ATP‐dependent proteolysis. Susceptibility is conferred on the mitochondria by a protein, the ‘mitochondria susceptibility factor’ which is synthesized during maturation of the reticulocytes in an iron‐containing medium.
Adenovirus infection reverses the antiviral state induced by human interferon
Authors: Feduchi Elena , Carrasco Luis
Published: July 2002

HeLa cells treated with human lymphoblastoid interferon do not synthesize poliovirus proteins. The antiviral state against poliovirus is reversed if cells are previously infected with adenovirus type 5. A late gene product seems to be involved in this reversion, since no effect is observed at early stages of infection or in the presence of aphidicolin.
ADP‐ or pyrophosphate‐dependent proton pumping of pea stem tonoplast‐enriched vesicles
Authors: Macrì Francesco , Vianello Angelo
Published: July 2002

Pea stem tonoplast‐enriched vesicles have an ADPase and PPiase activity capable of generating a transmembrane proton gradient (ΔpH) and an electric potential (Δψ). Both proton translocating activities have a pH optimum around 6.5, are Mg2+‐dependent, require the presence of a monovalent cation (K+, Rb+ or Cs+) and of a permeant anion, such as NO−
3, Cl− or Br−. They are almost completely inhibited by 50 μM DIDS, DES and DCCD, 50% inhibited by 100 μM molybdate and unaffected by Na3VO4 or KNO3. Hexokinase and ATP do not prevent H+‐ADPase and H+‐PPiase activity, thus indicating that these functions are not caused by an ATP‐dependent proton pumping and that they have catalytic sites different from those of H+‐ATPase, respectively. On the basis of these characteristics, ADP‐ and PPi‐dependent proton translocating activities seem carried out by a similar enzyme complex which appears different from the NO−
3‐inhibited, VO3−
4‐insensitive H+‐ATPase.
Binding of synthetic β‐human atrial natriuretic peptide to cultured rat vascular smooth muscle cells
Authors: Hirata Yukio , Yoshimi Hiroki , Takata Shoichiro , Matsubara Hiroaki , Takagi Yasuyuki , Iida Tatsuyoshi , Chino Naoyoshi , Watanabe Takushi X. , Kimura Terutoshi , Sakakibara Shumpei
Published: July 2002

We have studied the effects of synthetic β‐human atrial natriuretic peptide (β‐hANP), an antiparallel dimer of α‐hANP, on receptor binding and cGMP generation in cultured rat vascular smooth muscle cells and compared the effects with those of α‐hANP. Characteristics of temperature‐dependent binding and degradation of 125I‐β‐hANP were similar to those 125I‐α‐hANP. Scatchard analysis indicated a single class of binding sites for β‐hANP with a maximal binding capacity one‐half that of α‐hANP. Parallel and antiparallel dimers were equipotent in inhibiting the binding and stimulating intracellular cGMP formation, of which the maximal effect was about one‐half that of α‐hANP. Reverse‐phase high performance liquid chromatography revealed that most of β‐hANP added to cells was converted to a small molecular mass component corresponding to α‐hANP after incubation. These data suggest that the less potent effect of β‐hANP in receptor binding and cGMP generation may be partly accounted for by the possible conversion of β‐HANP to α‐hANP at the site of target cells.
Bacteriorhodopsin's M412 and BR605 protein conformations are similar Significance for proton transport
Authors: Marrero Hector , Rothschild Kenneth J.
Published: July 2002

Cation removal or acidification induces a transition of bacteriorhodopsin (BR568) to a blue species (BR605). Fourier transform infrared spectroscopy now reveals that the protein conformational changes accompanying this transition resemble those which occur during the BR568 to M412 transition and associated light‐driven proton transport. This and other results suggest that BR605 and M412 both have similar voltage‐dependent protein conformations in which a secondary structure is stabilized by a change in the local electric potential sensed by internal charged groups involved in proton transport.
A novel 60‐kDa smooth muscle protein that binds filamin‐actin filament complex
Authors: Maekawa Shohei , Sakai Hikoichi
Published: July 2002

From the low salt‐extracted debris of bovine stomach smooth muscle, a protein having a molecular mass of 60 kDa in SDS‐PAGE was newly isolated. Co‐sedimentation assay with actin filaments and several actin binding proteins such as filamin, α‐actinin, caldesmon and fodrin showed that this protein co‐sediments with actin only in the presence of filamin. Falling ball viscometric assay showed that this protein increases the viscosity of actin‐filamin solution in a dose‐dependent manner. Immunoblotting analysis showed specific localization of this protein in smooth and striated muscles.
Induction of c‐fos proto‐oncogene by a chemotactic peptide in human peripheral granulocytes
Authors: Itami Makiko , Kuroki Toshio , Nose Kiyoshi
Published: July 2002

The chemotactic peptide, fMet‐Leu‐Phe (fMLP), induced proto‐oncogene c‐&f;os MRNA in purified human peripheral granulocytes. The induction was transient, and was inhibited by pertussis toxin or by an inhibitor of protein kinase C. These results suggest that activation of a guanine nucleotide‐binding protein and of protein kinase C is involved in c‐&f;os induction in granulocytes.
Tissue‐specific binding of a nuclear factor to the insulin gene promoter
Authors: Sample Clare E. , Steiner Donald F.
Published: July 2002

Using a DNA‐binding gel mobility shift assay, a protein‐DNA complex was detected using the rat II insulin promoter and a nuclear extract from rat insulinoma cells. This complex was detected using extracts from other insulin‐producing cell lines but was not found using nuclear extracts from non‐insulin‐producing pancreatic cell lines or other cell types. Binding of the tissue‐specific protein to the labelled promoter fragment was effectively competed by both rat and human insulin genes but not by the SV40 TATA box. This protein‐DNA interaction may be involved in tissue‐specific regulation of insulin gene expression.
A 63 kDa protein is secreted from BALB/c‐3T3 cells entering the G1 phase from the G0 state
Authors: Tominaga Shin-ichi
Published: July 2002

A 63 kDa protein is detectable in the culture fluid of mouse BALB/c‐3T3 cells traversing from the G0, state to the G1 phase, whereas it is undetectable in the culture fluid of quiescent or growing BALB/c‐3T3 cells. Secretion of the protein is maximal at 10 h after serum addition. G0‐specific ts mutant cells (rat tsJT60) also secrete the 63 kDa protein only when the quiescent cells are stimulated by serum addition at permissive temperature. These facts indicate that the 63 kDa protein is secreted only from cells traversing from the G0, state to the G1, phase.
Specific and nonspecific effects of nucleotides on hormone‐induced phosphoinositide turnover in permeabilized human pituitary tumour cells (Flow 9000)
Authors: Lo William W.Y. , Hughes John
Published: July 2002

Previous studies have shown that agonist‐induced inositol phosphate formation in the human embryonic pituitary cell line Flow 9000 is regulated by guanine nucleotides, and it is likely that a guanine nucleotide‐binding protein is involved in coupling receptors to phosphoinositidase C (PIC) [(1986) Biochem.Soc. Trans. 14, 1135–1136]. We have now tested the specificity of various nucleotides in regulating PIC activity in the absence or presence of the hormone cholecystokinin (CCK‐8) in saponin‐permeabilized [3H]inositol‐labelled Flow 9000 cells. We found that all nucleotides tested (i.e. CTP, UTP, ITP, TTP, GTP, GppNHp, GTP[S], ATP, AppNHp and ATP[S]) stimulated total [3H]inositol phosphate (3H]IP) formation in a dose‐dependent manner with similar potency and efficacy. However, only guanine nucleotides significantly enhanced CCK‐8 stimulation of [3H]IP production. These results indicate a physiological role for guanine nucleotides in regulating hormone‐induced phosphoinositide turnover. In addition, the effects of nucleotides on calcium‐dependent PIC activity are discussed.
Electron paramagnetic resonance and magnetic circular dichroism studies of electron‐transfer flavoprotein‐ubiquinone oxidoreductase from pig liver
Authors: Johnson Michael K. , Morningstar Joyce E. , Oliver Melinda , Frerman Frank E.
Published: July 2002

Pig liver electron‐transfer flavoprotein‐ubiquinone oxidoreductase has been investigated by room temperature UV‐visible, low‐temperature electron paramagnetic resonance and low‐temperature magnetic circular dichroism spectroscopies. The results provide unambiguous evidence for the presence of a single [4Fe‐4S] cluster that is diamagnetic in the isolated enzyme and becomes paramagnetic with an S = , ground state on reduction with dithionite or enzymatically with the physiological electron donor. The EPR data for samples at pH 7.8 indicate that FAD is reduced by one electron to the anionic semiquinone form in the enzymatically reduced enzyme, and by two electrons to the hydroquinone form by excess dithionite. The possibility of weak spin‐spin interaction between the FAD semiquinone and the [4Fe‐4S]1+ center is discussed in the light of the observation of a small increase in the linewidth of the Fe‐S EPR in enzymatically reduced samples.
Arginine‐vasopressin stimulates the formation of phosphatidic acid in rat Leydig cells
Authors: Nielsen Jane R. , Hansen Harald S. , Jensen Benny
Published: July 2002

Arginine‐vasopressin (AVP) stimulated the formation of labelled phosphatidic acid (PA) in [14C]arachidonic acid‐prelabelled rat Leydig cells. After addition of 10t̄6M AVP [14C]arachidonoylphosphatidic acid reached a maximum within 2 min. The increase was dose‐dependent (10−11−10−6 M). No change in labelling of other phospholipids and diacylglycerol could be detected. The V1 antagonist dPTyr(Me)AVP inhibited in a dose‐dependent manner the AVP‐stimulated accumulation of PA. The V2 agonist dPVDAVP was without effect. The present results suggest that AVP binds to V1 receptors in rat Leydig cells resulting in stimulation of PA turnover. We suggest that the AVP‐stimulated PA formation is an indication of phosphoinositide turnover.
Glucose regulates preproinsulin messenger RNA levels in a clonal cell line of simian virus 40‐transformed B cells
Authors: Hammonds Peter , Schofield Paul N. , Ashcroft Stephen J.H.
Published: July 2002

In HIT‐T15 cells grown in the absence of glucose, Northern blot analysis of total RNA revealed a major 0.5 kb preproinsulin (ppI) mRNA transcript which co‐migrated with the mature transcript from a human insulinoma. In 4 h tissue cultures, glucose (2–20 mM) stimulated HIT cell ppI mRNA levels in a markedly dose‐dependent manner. Glucose‐stimulated ppI mRNA was (i) inhibited by actinomycin D, suggesting that regulation may be in part transcriptional, and (ii) potentiated by agents known to activate B cell protein kinases. HIT cells represent a unique model for investigating long term regulation of insulin gene expression and biosynthesis.
Permeabilization of thymocytes by photon activation of erythrosin
Authors: Yonuschot G. , Matthews E.K. , Corps A.N. , Metcalfe J.C.
Published: July 2002

Thymocytes previously loaded with quin 2 were rapidly permeabilized by the photon activation of erythrosin and the rate of permeabilization monitored by measuring fluorimetrically the increasing saturation of quin 2 with calcium. The extent of permeabilization was assessed also by the loss of [3H]quin 2 from the thymocytes and penetration of the cells by eosin and trypan blue. Lactate dehydrogenase leakage from the permeabilized cells was markedly delayed compared to the rapid increase in permeability to calcium and quin 2. The rate of permeabilization was dependent upon the concentration of erythrosin, the duration of illumination, the presence of oxygen, and the temperature. These results are consistent with the rapid photochemical generation of highly reactive singlet oxygen which alters thymocyte membrane structure and permeability.
Reannealing of phalloidin‐treated actin filaments during recovery after sonication and its inhibition by β‐actinin
Authors: Oosawa Masatake , Maruyama Koscak
Published: July 2002

Phalloidin (2 mol per mol actin)‐treated pyrenyl F‐actin showed a critical concentration of 1.8 μM in the presence of 10 mM KCl, 0.2 mM ADP, and 5 mM Tris‐HCl buffer, pH 8.0 at 25°C. The filament weight concentration did not change at all during and after sonication, yet degrees of flow birefringence increased and the filament number concentration decreased after the termination of sonication. The latter changes were not affected by EDTA, but inhibited by β‐actinin. These observations suggest that reannealing of short pieces of phalloidin‐treated actin filaments fragmented during sonication takes place during recovery after sonication.
Cloning and sequencing of cDNA that encodes goat growth hormone
Authors: Yamano Yoshiaki , Oyabayashi Kazuo , Okuno Mitsuhiro , Yato Miki , Kioka Noriyuki , Manabe Eichi , Hashi Hidetaka , Sakai Hiroshi , Komano Tohru , Utsumi Kyozo , Iritani Akira
Published: July 2002

The cDNA that encodes goat growth hormone (gGH) was isolated from a goat pituitary cDNA library. The cDNA, about 880 base pairs long, had a coding sequence, 5′‐ and 3′‐untranslated regions and a poly(A) chain. The cDNA could encode a polypeptide of 217 amino acids. The amino acid sequence homology between gGH and the sequences of bovine GH, rat GH and human GH was 99, 83 and 66%, respectively. By Northern blot hybridization, we found that the possible gGH gene is transcribed in the goat pituitary.
DNA cleavage based on high voltage electric pulse
Authors: Tamiya Eiichi , Nakajima Yoshiko , Kamioka Hiroyuki , Suzuki Masayasu , Karube Isao
Published: July 2002

A high voltage electric pulse was applied to DNA cleavage. The DNA cleavage reaction was dependent on the voltage amplitude, pulse number and pulse width. Radical scavengers and ESR data indicated the possibility that active species such as OH radical were strongly related to DNA cleavage.
Horse brain acylphosphatase: Purification and characterization
Authors: Stefani M. , Berti A. , Camici G. , Manao G. , Degl'Innocenti D. , Prakash G. , Marzocchini R. , Ramponi G.
Published: July 2002

Two structurally different acylphosphatases found in horse brain were purified; they were not immunologically related. The molecular masses were almost identical and the kinetic parameters were rather similar. The data reported indicate that one of the purified brain acylphosphatases and an enzyme, previously isolated from horse muscle, are the same protein. The presence of this acylphosphatase form in the brain has not been reported before. The other acylphosphatase seemed to be the same as the enzyme which had been purified from calf brain and partially characterized by Diederich and Grisolia [(1969) J. Biol. Chem. 244, 2412–2417]. Furthermore, this enzyme seems to be identical to the acylphosphatase recently purified in our laboratory from human erythrocytes.
Thymopoietins and long postsynaptic neurotoxins share common information in their primary structures
Authors: Skerl Vesna , Pavlović Mirjana
Published: July 2002

The informational content of the primary structure of thymopoietin (TP) is investigated using the informational spectrum method (ISM). We show that the sequence of TP shares common information with the sequences of long postsynaptic snake neurotoxins, although no apparent similarity was found among their primary structures. The most sensitive point in the sequence of TP, concerning this information, is D‐34, previously determined as being the residue responsible for TP's effect on neuromuscular transmission. Our results suggest that TP and long toxins recognize the neuromuscular nicotinic acetylcholine receptor (AChR) and/or bind to the AChR in a different mode than the short toxins do.
Purification and properties of a β‐galactosyl‐specific lectin from the fruiting bodies of Ischnoderma resinosus
Authors: Kawagishi H. , Mizuno T.
Published: July 2002

This lectin is composed of two identical subunits of 16 kDa. It exhibits specificity towards β‐galactosyl residues.
Dissociation between intracellular calcium mobilization and insulin secretion in isolated rat islets of Langerhans
Authors: Morgan Noel G. , Hurst Roger D.
Published: July 2002

The neuropeptide bombesin provoked a dose‐dependent stimulation of 45Ca2+ efflux from pre‐loaded islets of Langerhans. This response occurred rapidly, was not sustained and did not depend on the presence of extracellular calcium, suggesting that it resulted from the mobilization of intracellular calcium stores. Under conditions when large increases in 45Ca2+ efflux were observed, bombesin completely failed to stimulate the rate of insulin secretion. Similar results were also obtained with the muscarinic cholinergic agonist, carbachol. The data suggest that the release of calcium from intracellular pools is not sufficient to induce an increase in insulin secretion in normal islet cells.
Similar short elements in the 5′ regions of the STA2 and SGA genes from Saccharomyces cerevisiae
Authors: Pardo J.M. , Iáñez E. , Zalacaín M. , Claros M.G. , Jiménez A.
Published: July 2002

The 5′ regions of the SGA and ST A2 genes, encoding the intra‐ and extracellular glucoamylases, respectively, from Saccharomyces cerevisiae have been sequenced. In addition, the transcription initiation sites have been determined. Four distinct short elements (named I to IV) were found in both genes. Element III has the consensus sequence PuCATTTAPiG with a bilateral symmetry around the central T, and is present in both genes as a direct repeat. This motive seems responsible for the coregulation of ST A2 and SGA by the repressor ST A10 gene of S. cerevisiae.
Modes of action of uncouplers in thylakoids I. Proton conduction characteristics
Authors: Schönfeld Mordechay , Schickler Hedva
Published: July 2002

A formal description of proton efflux from chloroplasts as a function of proton concentrations inside and outside the thylakoids, was used to analyze effects of uncouplers and energy transfer inhibitors on proton conduction in thylakoids. Plots of proton efflux vs ΔpH, obtained with NH4Cl, matched simulated curves portraying increases of proton permeability. Effects of DCCD fitted those expected for blocking CF0‐CF1 channels. Unexpectedly, effects of gramicidin or FCCP on proton conduction indicated that interference with proton efflux via CF0‐CF1, and not stimulation of proton leakage, was the direct cause for inhibition of photophosphorylation by these uncouplers.
Heme‐linked ionization and ligand binding produce identical changes of proximal heme stereochemistry in reduced horseradish peroxidase Evidence for existence of two protein conformations
Authors: Sharonov Yurii A. , Pismensky Victor F. , Yarmola Elena G.
Published: July 2002

The visible and near infrared magnetic circular dichroism spectra of chemically reduced horseradish peroxidase at neutral and alkaline pH values and 5‐coordinate protoheme‐(2‐methylimidazole) at pH 9.1 were compared at 4.2 K with those of photolysis products of their carbon monoxide complexes. From the results obtained we concluded that: (i) there are two protein conformations of HRP which determine the geometry of the Fe‐N(His) bond; (ii) the transition from one conformation (heme stereochemistry) to another can be induced by either heme‐linked ionization or ligand binding; (iii) a trigger mechanism for switching between two conformations has to exist.
Vestiges of lost introns in the thermal stability map of DNA
Authors: Hanai Ryo , Suyama Akira , Wada Akiyoshi
Published: July 2002

The absence of introns in prokaryotic genes has been explained by intron loss on various bases. Here we report another piece of evidence on intron loss, which was found in the thermal stability map of DNA. We calculated the local melting temperature of cDNA sequences and found that (i) gaps in thermal stability tend to occur near intron positions with a statistical significance, and (ii) one‐third of the gaps far from intron positions can be assigned to lost introns. From these results we conclude that the gaps of thermal stability in protein coding regions are the vestiges of lost introns.
The nucleotide sequence of the genes coding for the S19 and L22 equivalent ribosomal proteins from Halobacterium halobium
Authors: Mankin Alexander S.
Published: July 2002

The primary structure of the two ribosomal protein genes of archaebacterium Halobacterium halobium has been determined. The encoded polypeptides are homologous to the Escherichia coli ribosomal proteins S19 and L22. The two genes constitute part of an operon whose organization is analogous to that of the ‘S10’ operon of E. coli.
Activation of an insulin‐stimulated S6 kinase in 3T3 L1 cell‐free extracts by proteolysis
Authors: de Herreros Antonio Garcia
Published: July 2002

Using chromatography on a Fast S‐Sepharose column, the insulin‐stimulated S6 kinase can be resolved from other S6 kinases present in 3T3 L1 cell extracts. Only one S6 kinase is greatly activated by insulin (4–5‐fold) and phosphorylates S6 with a high stoichiometry (4–5 mol phosphate per mol S6). This insulin‐dependent S6 kinase can be activated in cell‐free extracts by incubation with high concentrations of Ca2+. This activation is blocked by protease inhibitors such as leupeptin and is mimicked by trypsin. The stimulation does not require the presence of the protein kinase dependent on phospholipids and calcium (PK‐C) in the cell extracts. The level of stimulation produced by proteolysis in the cell extracts is comparable to that reached in vivo by incubation with insulin.
The gate of mitochondrial porin channel is controlled by a number of negative and positive charges
Authors: Mirzabekov Tajib A. , Ermishkin Lev N.
Published: July 2002

Negatively charged carboxyl groups of mitochondrial porin have been converted into positively charged ones by means of reaction with water‐soluble carbodiimide in the presence of ethylenediamine. Properties of channels formed in a planar lipid bilayer by native and modified porins are compared. Amidation has only little influence on the porin channel‐forming activity as well as on the open‐state conductance of the channel. However, the modification results in a significant enhancement of the voltage dependence of the channel gating and in an increase of the anionic selectivity. It is suggested that the voltage sensor of the porin channel gate is composed of a number of negative (> 14) and positive (> 22) charges.
Heterogeneous distribution of nuclear triiodothyronine receptors in liver and preadipose cells as evidenced by their reactivity to antibodies against different protein products of erb A oncogenes
Authors: Torresani J. , Ghysdael J. , Bismuth J. , Teboul M. , Ghiringhelli O. , Savary J.
Published: July 2002

Polyclonal antibodies raised in rabbits against bacterially produced peptides in the C‐terminal region of v‐erb A or human c‐erb Aα oncogenes recognize the nuclear triiodothyronine (T3) receptors in the T3‐sensitive Ob 17 mouse preadipocyte cell line and not in mouse or rat liver. The results confirm the existence of different T3 receptors in different tissues. The results also suggest a heterogeneous receptor distribution within the preadipose cell line, with a predominance of c‐erb Aα‐type species. Antibodies raised against domain 149–227, but not against domain 245–325, impair T3 binding, suggesting a role for this domain in ligand binding.
A small basic ribosomal protein in Sulfolobus solfataricus equivalent to L46 in yeast: Structure of the protein and its gene
Authors: Ramirez Celia , Louie K.Andrea , Matheson Alastair T.
Published: July 2002

The structure of the gene for a small, very basic ribosomal protein in Sulfolobus solfataricus has been determined and the structure of the protein coded by this gene (L46e) has been confirmed by partial amino acid sequencing. The protein shows substantial sequence homology to the eukaryotic ribosomal proteins L39 in rat and L46 in yeast. There is no sequence homology to any of the eubacterial ribosomal proteins suggesting that this protein is absent in the eubacterial ribosome.
Disposition of water in chloroplast coupling factor 1 (CF1)
Authors: Ibel Konrad , Engelbrecht Siegfried , Wagner Richard , Andreo Carlos S. , Junge Wolfgang
Published: July 2002

Small‐angle neutron scattering experiments were performed in dilute aqueous solutions of chloroplast F1‐ATPase. By contrast variation in 1H2O/2H2O mixtures and when using different concentrations of glycerol in 2H2O, structural information on the spatial distribution of dry protein and water was obtained. The maximum distance within latent and active CF1 was 12 nm. the shape of CF1 was globular. The total volume of CF1 was 900 nm3, and its dry volume (excluding the volume of one water molecule per two exchangeable hydrogen atoms) was 400 nm3. A volume of 670 nm3 was inaccessible to glycerol at low glycerol concentrations (less than 25%). At higher concentrations (up to 50%) a volume of 460 nm3 was excluded to glycerol. Within the resolution of our experiment (1.6 nm) there was no evidence for particular water‐rich regions or of secluded water spaces or any particular places for glycerol exchange. Upon thiol activation of the latent enzyme only small changes in structure were detectable just at the limits of the experimental error. They suggest an enhancement of the surface roughness.
Energy profiles in the acetylcholine receptor (AChR) channel The MII‐helix model and the role of the remaining helices
Authors: Furois-Corbin S. , Pullman Alberte
Published: July 2002

It is demonstrated by theoretical computations that no favorable energy profile for cation transfer can be obtained in a model of the AChR channel constructed with the sole five MII helices of the inner wall. A favorable profile is obtained upon including the effect of the remaining helices of the five subunits. The decisive role, for the exit of the ion, of the charged residues situated at the N‐terminal of the MII segments, established before, is underlined further. The role of the other elements of the channel wall (peptide carbonyl oxygens, hydrocarbon residues and polar side chains) is analyzed.
Regulation of human tyrosine hydroxylase activity Effects of cyclic AMP‐dependent protein kinase, calmodulin‐dependent protein kinase II and polyanion
Authors: Okuno Sachiko , Kanayama Yoshiharu , Fujisawa Hitoshi
Published: July 2002

To determine the regulatory mechanism for human tyrosine hydroxylase, we examined modulations of the activity of the enzyme from human pheochromocytoma by cyclic AMP‐dependent protein kinase, calmodulin‐dependent protein kinase II and polyanion. The most remarkable activation was observed when the enzyme was assayed at physiological pH (pH 7) after being subjected to phosphorylation by cyclic AMP‐dependent protein kinase. Calmodulin‐dependent protein kinase II and polyanion also modulated the enzyme activity. The results suggest that tyrosine hydroxylase may be regulated similarly in both human and rat.
Identification of a mutation in Escherichia coli F1‐ATPase β‐subunit conferring resistance to aurovertin
Authors: Lee Rita S.-F. , Pagan Janet , Satre Michel , Vignais Pierre V. , Senior Alan E.
Published: July 2002

A mutation conferring aurovertin resistance on Escherichia coli F1‐ATPase was identified as R398 → in the F1 β‐subunit. β‐subunit from the mutant doe not bind aurovertin; therefore our results suggest the region of sequence around residue β‐398 is involved in aurovertin binding. Since nucleotide and aurovertin binding to isolated β‐subunit are not mutually exclusive, the data further suggest that the β‐subunit catalytic nucleotide‐binding domain does not include residue 398. The mutation prevented aurovertin inhibition of ATPase at pH 6 and 8.5, implying charge on the arginine side‐chain is not a major determinant of aurovertin binding or that the pK of R398 is shifted due to a peculiar environment. The equivalent residue is usually arginine in F1 β‐subunits of different species; notably in the aurovertin‐insensitive thermophilic bacterium PS3 F1‐ATPase, this residue is phenylalanine.
Identification of a proteolipid oligomer as a constituent part of CF0, the proton channel of the chloroplast ATP synthase
Authors: Lill Holger , Junge Wolfgang
Published: July 2002

We studied the action of the photophosphorylation inhibitor, N,N′‐dicyclohexylcarbodiimide (DCCD) on the channel portion (CF0) of the chloroplast ATP synthase (CF0CF1). We found that the target for binding of [14C]DCCD was an oligomer of the small proteolipid‐subunit (subunit III) of CF0. We treated thylakoids with low concentrations of DCCD, sufficient to inhibit photophosphorylation. The 14C‐labelled inhibitor was found on polyacrylamide gels in a position corresponding to an apparent molecular mass of 50 kDa. This band comprised a homooligomer of proteolipid subunits of CF0. At higher concentrations of DCCD, it fell apart into proteolipid monomers. This dissociation was prevented by the presence of venturicidin, another CF0 inhibitor acting on the proteolipid subunit, during the incubation with DCCD. The existence of such an oligomeric substructure in CF0 is discussed in the light of diverging structural models for the proton channel of F0F1‐type ATPases.
Influenza neuraminidase is delivered directly to the apical surface of MDCK cell monolayers
Authors: Daniels Phillipa U. , Edwardson J.Michael
Published: July 2002

The aim of this study was to investigate whether influenza neuraminidase travels directly from the Golgi complex to the apical domain of the plasma membrane in virally infected epithelial (MDCK) cell monolayers, or whether it passes transiently through the basolateral domain. Using a new assay for the delivery of neuraminidase to the plasma membrane, we found that the time course of transport of this protein from the Golgi complex to the apical surface of MDCK cell monolayers was very similar to that for influenza haemagglutinin, which is known to be delivered directly to its destination. In addition, a similar time course of neuraminidase transport was found in BHK cells, which are not asymmetric and in which delivery must therefore be direct. Finally, basolateral exposure of MDCK cell monolayers grown on nitro‐cellulose filters to an anti‐neuraminidase antibody was shown to have no effect on the delivery of active neuraminidase to the apical surface. We conclude from these results that neuraminidase, like haemagglutinin, is delivered directly to the apical surface.
An archaebacterial gene from Methanococcus vannielii encoding a protein homologous to the ribosomal protein L10 family
Authors: Köpke Andreas K.E. , Baier Gottfried , Wittmann-Liebold Brigitte
Published: July 2002

An open reading frame upstream of the Methanococcus vannielii L12 gene has been detected. The beginning of this open reading frame agrees with the N‐terminal region of a protein (MvaL10) which has been isolated from the 50 S ribosomal subunit of M. vannielii and sequenced. The length of this gene is 1008 nucleotides, coding for 336 amino acids. Excellent sequence similarities were found to the L10‐like ribosomal proteins from Halobacterium halobium and man. The N‐terminal part of the MvaL10 protein shows significant sequence similarities to the E. coli L10 protein. MvaL10 is more than twice as long as E. coli L10 but is of length similar to those of the homologous halobacterial and human proteins. Interestingly, the C‐terminal region of MvaL10 shows exceptionally high similarity to the C‐terminal sequence of the MvaL12 protein. This is not the case for the E. coli proteins but was also observed for the human, Halobacterium and Sulfolobus proteins.
Heat‐stable translational inhibitor from rabbit reticulocyte lysates
Authors: Gaitero Fuencisla , Mendez Enrique , de Haro Cesar
Published: July 2002

We have purified to apparent homogeneity a heat‐stable (HS) factor from the postribosomal supernatant of rabbit reticulocyte lysates [(1988) FEBS Lett. 236, 479‐483]. HS inhibits translation in hemin‐supplemented lysates and induces phosphorylation of the α‐subunit of the eukaryotic initiation factor 2 as does hemin deficiency. The translational inhibition produced by addition of HS to hemin‐containing reticulocyte lysates and the accompanying phosphorylation of the eIF‐2α subunit can be prevented or reversed by NADPH generators including glucose 6‐phosphate, NADPH itself, and also by dithiols, e.g., dithiothreitol, but not by fructose 1,6‐bisphosphate or by monothiols, e.g., 2‐mercaptoethanol. When added to crude preparations of the proinhibitor form (proHCI) of the heme‐controlled translational inhibitor (HCI), HS produces a pronounced increase of the HCI to proHCI ratio. It appeared possible that HS might be oxidized gluatathione (GSSG) but this is not the case, for HS is not a substrate for highly purified glutathione reductase from rabbit erytrocytes. The spectral analysis of highly purified HS is consistent with the idea that HS could be a nucleotide derivative.
Formation of a duplex structure by an a‐octathymidylate: circular dichroism studies
Authors: Durand M. , Thuong N.T. , Maurizot J.C.
Published: July 2002

Oligonucleotide, α‐; CD; Thermodynamic parameter
Kinetoplast DNA‐aggregating proteins from the parasitic protozoan Crithidia fasciculata
Authors: Tittawella Ivor
Published: July 2002

Proteins from C. fasciculata, which preferentially aggregate the parasite's AT‐rich mitochondrial (kinetoplast) DNA in vitro, are reported. The aggregation is non‐topological, non‐covalent, independent of Mg2+ and ATP, but much improved by spennidine. We discuss how these proteins might modulate the shape and size of the parasite's mitochondrial genome.
The calcium ATPase of sarcoplasmic reticulum is inhibited by one Ca2+ ion
Authors: Khananshvili D. , Myung J. , Kolouch R. , Jencks W.P.
Published: July 2002

Inhibition by calcium of the steady‐state turnover of the calcium ATPase from sarcoplasmic reticulum of rabbit muscle follows a Hill slope of 0.8 ± 0.2 (pH 7.0, 0.1 M KCl, varying [Mg2+] and 2 μM A23187 ionophore). It is concluded that dissociation of the two Ca2+ ions from E‐P·Ca2 is sequential and that the inhibition arises from the binding of one Ca2+ to A‐P·Ca1.
Chronic stimulation‐induced effects point to a coordinated expression of carbonic anhydrase III and slow myosin heavy chain in skeletal muscle
Authors: Jeffery S. , Kelly C.D. , Carter N. , Kaufmann M. , Termin A. , Pette D.
Published: July 2002

Chronic low‐frequency Stimulation of rat fast‐twitch muscle induces 3.7‐fold elevations in cytochrome c oxidase activity, but remains without effect on carbonic anhydrase III (CAIII) mRNA and protein. This is in contrast with the situation in the rabbit where chronic stimulation elicits more than 10‐fold elevations in CAIII activity and mRNA content which coincide with an enhanced expression of the slow myosin heavy chain (HCI). Since chronic stimulation of rat muscle does not enhance the expression of HCI, we conclude that CAIII is expressed in parallel with HCI and, therefore, is present only in type I and C fibers.
Fatty acid acylation of lens fiber plasma membrane proteins
Authors: Manenti Stéphane , Dunia Irène , Benedetti E.Lucio
Published: July 2002

We describe in this report the fatty acylation of some of the main polypeptides from the eye lens fibers. MP26, the major lens fiber plasma membrane protein, and probably MP22, its natural degradation product, are palmitoylated in a post‐translational process. This is also the case for α‐crystallin, a major cytoplasmic structural protein shown to interact directly with the plasma membrane. Furthermore, a 65 kDa non‐identified polypeptide and a high molecular weight component are also modified in the same way.
Rate enhancement of the electron transfer of the adrenodoxin‐adrenodoxin reductase system by inorganic and nucleotide phosphates
Authors: Yamano Toshio , Nonaka Yasuki , Miura Retsu
Published: July 2002

Phosphate and pyrophosphate increased the rate of reduction of adrenodoxin by NADPH‐adrenodoxin reductase and NADPH, pyrophosphate being one order more effective than the former. However, the cytochrome c reduction by the electron transport system was inhibited in the presence of inorganic (pyro)ptiosphate. On the other hand, ADP and ATP enhanced the rates of reduction of both adrenodoxin and cytochrome c through adrenodoxin by the electron transport system. GTP also enhanced the rate of reduction of cytochrome c by this system, whereas AMP showed no appreciable enhancement. These inorganic and nucleotide phosphates did not affect the rate of ferricyanide reduction by the reductase.
Functional expression of the mutants of the chloroplast tRNALys gene from the liverwort, Marchantia polymorpha, in Escherichia coli
Authors: Nakahigashi Kenji , Inokuchi Hachiro , Ozeki Haruo
Published: July 2002

The anticodon of the tRNALys gene (trnK) in the liverwort, Marchantia polymorpha, was anificially converted to an amber anticodon. This mutant tRNALys(CTA) gene carrying either the intron or the C27‐C43 mismatch at the anticodon‐stem is not functional in Escherichia coli, but without both of them, it does work as a tRNALys amber suppressor.