bluuebunny/crossref_metadata_2025_split huggingface dataset:
Purchasing and Social Responsibility: A Replication and Extension
Authors: Carter Craig R. 
Published: April 2006

SUMMARYSocially responsible purchasing continues to be an area of interest from both managerial and scholarly perspectives. Socially responsible purchasing has implications for all elements of the supply chain, including suppliers, employees and customers, among others. This article empirically examines purchasing social responsibility (PSR) across a large sample of manufacturing and service organizations. It is a replication of earlier work on PSR within consumer products industries. The article models PSR across the following five constructs: diversity, the environment, human rights, philanthropy and community, and safety. Findings and specific managerial implications are presented.
A Holistic Approach to New Product Development: New Insights
Authors: Tracey Michael 
Published: April 2006

SUMMARYThe literature for some time has endorsed a participative approach to new product development. Nonetheless, practice still seldom follows theory. The production, purchasing and logistics areas, as well as suppliers and customers, continue to be underrepresented at many manufacturing firms. This research provides empirical support for including these parties early in new product development. It demonstrates the positive impact their participation can have on manufacturing efficiency and agility, delivery service and organizational performance. It also reveals that there is ample room to increase their participation at many firms.
Reducing the number of fixed points of some homeomorphisms on nonprime "Equation missing" -manifolds
Authors: Zhao Xuezhi 
Published: April 2006

AbstractWe will consider the number of fixed points of homeomorphisms composed of finitely many slide homeomorphisms on closed oriented nonprime "Equation missing"-manifolds. By isotoping such homeomorphisms, we try to reduce their fixed point numbers. The numbers obtained are determined by the intersection information of sliding spheres and sliding paths of the slide homeomorphisms involved.
Fixed point theorems in locally convex spaces—the Schauder mapping method
Authors: Cobzaş S 
Published: April 2006

AbstractIn the appendix to the book by F. F. Bonsal, Lectures on Some Fixed Point Theorems of Functional Analysis (Tata Institute, Bombay, 1962) a proof by Singbal of the Schauder-Tychonoff fixed point theorem, based on a locally convex variant of Schauder mapping method, is included. The aim of this note is to show that this method can be adapted to yield a proof of Kakutani fixed point theorem in the locally convex case. For the sake of completeness we include also the proof of Schauder-Tychonoff theorem based on this method. As applications, one proves a theorem of von Neumann and a minimax result in game theory.
Fixed point theorems in generating spaces of quasi-norm family and applications
Authors: Xiao Jian-Zhong , Zhu Xing-Hua 
Published: April 2006

AbstractSome new concepts of generating spaces of quasi-norm family are introduced and their linear topological structures are studied. These spaces are not necessarily locally convex. By virtue of some properties in these spaces, several Schauder-type fixed point theorems are proved, which include the corresponding theorems in locally convex spaces as their special cases. As applications, some new fixed point theorems in Menger probabilistic normed spaces and fuzzy normed spaces are obtained.
Coincidence classes in nonorientable manifolds
Authors: Vendrúscolo Daniel 
Published: April 2006

AbstractWe study Nielsen coincidence theory for maps between manifolds of same dimension regardless of orientation. We use the definition of semi-index of a class, review the definition of defective classes, and study the occurrence of defective root classes. We prove a semi-index product formula for lifting maps and give conditions for the defective coincidence classes to be the only essential classes.
Coincidence and fixed point theorems for functions in "Equation missing" -KKM class on generalized convex spaces
Authors: Kuo Tian-Yuan , Huang Young-Ye , Jeng Jyh-Chung , Shih Chen-Yuh 
Published: April 2006

AbstractWe establish a coincidence theorem in "Equation missing"-KKM class by means of the basic defining property for multifunctions in "Equation missing"-KKM. Based on this coincidence theorem, we deduce some useful corollaries and investigate the fixed point problem on uniform spaces.
Wecken type problems for self-maps of the Klein bottle
Authors: Gonçalves DL , Kelly MR 
Published: April 2006

AbstractWe consider various problems regarding roots and coincidence points for maps into the Klein bottle "Equation missing". The root problem where the target is "Equation missing" and the domain is a compact surface with non-positive Euler characteristic is studied. Results similar to those when the target is the torus are obtained. The Wecken property for coincidences from "Equation missing" to "Equation missing" is established, and we also obtain the following 1-parameter result. Families "Equation missing" which are coincidence free but any homotopy between "Equation missing" and "Equation missing", "Equation missing", creates a coincidence with "Equation missing". This is done for any pair of maps such that the Nielsen coincidence number is zero. Finally, we exhibit one such family where "Equation missing" is the constant map and if we allow for homotopies of "Equation missing", then we can find a coincidence free pair of homotopies.
Geometric and homotopy theoretic methods in Nielsen coincidence theory
Authors: Koschorke Ulrich 
Published: April 2006

AbstractIn classical fixed point and coincidence theory, the notion of Nielsen numbers has proved to be extremely fruitful. Here we extend it to pairs "Equation missing" of maps between manifolds of arbitrary dimensions. This leads to estimates of the minimum numbers MCC "Equation missing" (and MC "Equation missing", resp.) of path components (and of points, resp.) in the coincidence sets of those pairs of maps which are "Equation missing". Furthermore we deduce finiteness conditions for MC "Equation missing". As an application, we compute both minimum numbers explicitly in four concrete geometric sample situations. The Nielsen decomposition of a coincidence set is induced by the decomposition of a certain path space "Equation missing" into path components. Its higher-dimensional topology captures further crucial geometric coincidence data. An analoguous approach can be used to define also Nielsen numbers of certain link maps.
Apical sorting of ADAMTS13 in vascular endothelial cells and Madin-Darby canine kidney cells depends on the CUB domains and their association with lipid rafts
Authors: Shang Dezhi , Zheng X. Wu , Niiya Masami , Zheng X. Long 
Published: April 2006

AbstractADAMTS13 biosynthesis appeared to occur mainly in hepatic stellate cells, but detection of ADAMTS13 mRNA in many other tissues suggests that vascular endothelium may also produce ADAMTS13. We showed that ADAMTS13 mRNA and protein were detectable in human umbilical vein endothelial cells, aortic endothelial cells, and endothelium-derived cell line (ECV304). ADAMTS13 in cell lysate or serum-free conditioned medium cleaved von Willebrand factor (VWF) specifically. ADAMTS13 and VWF were localized to the distinct compartments of endothelial cells. Moreover, ADAMTS13 was preferentially sorted into apical domain of ECV304 and Madin-Darby canine kidney (MDCK) cells. Apical sorting of ADAMTS13 depended on the CUB domains and their association with lipid rafts. A mutation in the second CUB domain of ADAMTS13 (4143-4144insA), naturally occurring in patients with inherited thrombotic thrombocytopenic purpura, resulted in a significant reduction of ADAMTS13 secretion and a reversal of its polarity in MDCK cells. These data demonstrated that ADAMTS13 is synthesized and secreted from endothelial cells; the apically secreted ADAMTS13 from endothelial cells may contribute significantly to plasma ADAMTS13 proteases. The data also suggest a critical role of the CUB domains and a novel cargo-selective mechanism for apical sorting of a soluble ADAMTS protease in polarized cells.
Novel Functional Group Transformation from Acetylene Cobalt Complex to Ketone via Ligand Exchange
Authors: Hamajima Akinari , Nakata Hiyoku , Goto Masako , Isobe Minoru 
Published: April 2006

Abstract
A new transformation of acetylene dicobalt tetracarbonyl dppm complexes was found to convert to ketones with high regioselectivity under ligand exchange condition.
Carbonic Anhydrases (α‐Class)
Authors: Duda David M , McKenna Robert 
Published: April 2006

AbstractCarbonic anhydrases (CAs) are zinc metalloenzymes that catalyze the hydration of carbon dioxide and the dehydration of bicarbonate:, a process that has physiological importance in respiration, acid–base homeostasis, photosynthesis, and biosynthetic pathways. The α‐class of CA (and the CA domains in more complex isoforms) is monomeric with a molecular weight of approximately 30 kDa. At present, 14 isoforms of the α‐class are known with varying tissue distributions and catalytic activity. The catalytic turnover number of CAs varies from the maximal rate of 106s−1for isozyme II to 103s−1for isozyme III. The central structural motif of the α‐CAs can be described as a 10‐stranded twisted β‐sheet, which is flanked by seven α‐helices. The active‐site cavity consists of a single zinc ion tetrahedrally coordinated by three histidine residues (His94, 96, and 119) and a bound water molecule. In most of the α‐CAs, the resultant proton formed by the dehydration reaction of bicarbonate is transferred to bulk solution through the formation of a proton wire, mediated by residue His64, that lies at the mouth of the active site. Known inhibitors of CAs have been shown to bind to the metal ion and displace the zinc‐bound water, whereas activators have been shown to bind at the entrance of the active site and mimic the characteristics of the proton‐shuttling residue His64.
Streptomyces AlbusGD‐Ala‐D‐Ala Carboxypeptidase
Authors: Charlier Paulette , Wery Jean‐Pierre , Dideberg Otto , Frère Jean‐Marie 
Published: April 2006

AbstractThe zincD‐Ala‐D‐Ala carboxypeptidase hydrolyzes the C‐terminal peptide bond of peptides of general structure R‐D‐Ala‐D‐Xaa. The lytic activity of the enzyme and its extracellular location suggest that it might be used byStreptomycesfor fighting competitors in its ecological niche since the enzyme does not hydrolyze theStreptomycespeptidoglycan.The sequence of the 213‐residue mature protein is related to the VanX, VanY, and VanXY proteins of vancomycin‐resistant enterococci. The molecule is an ellipsoid consisting of two globular domains in which the N‐terminal and the C‐terminal ends are pulled apart. The small N‐terminal domain, from residue Asp1 to Pro83, has an all‐α‐helices structure and exhibits a typical three‐helix bundle fold, characteristic of the peptidoglycan binding domain. The largest C‐terminal domain belongs to the α + β type secondary structure, and is related to the N‐terminal domain of the murine sonic hedgehog, a signaling protein involved in natal morphogenesis and formation of embryonic patterning centers, and to the VanXD‐Ala‐D‐Ala dipeptidase ofEnterococcus faecium, a protein involved in the vancomycin resistance systems in streptococci. The mixed five‐stranded β‐sheet forms the core of the C‐terminal domain and the lining of one side of the catalytic cavity. One zinc ion occupies a roughly central position in the active site and is coordinated by the His154 NE2, the Asp161 OD1, and the His197 ND1. Classical β‐lactam compounds, which readily inactivate active site serineDD‐peptidases, are very sluggish inactivators of the zincD‐Ala‐D‐Ala carboxypeptidase. The best competitive inhibitors are thiol derivatives such as 2‐ and 3‐mercaptopropionate (Ki = 50 and 5 nM) that might behave as bidentate ligands of the Zn2+ion.
Leucine Aminopeptidase
Authors: Sträter Norbert , Lipscomb William N 
Published: April 2006

AbstractLeucine aminopeptidase belongs to the metallohydrolase family M17. In this family, two X‐ray diffraction structures are known for bovine lens LAP (blLAP) and for theEscherichia coliaminopeptidase A (PepA). These two peptidases are large homohexamers of 32 symmetry, and both have a large central solvent cavity near the active sites. Each active center contains two Zn2+separated by 3.0 Å. In PepA, maximal activity occurs in the presence of Mn2+. blLAP is activated by Mn2+, Mg2+or Co2+, but zinc is bound most strongly and is supposed to be the physiological cofactor. In the proposed catalytic mechanism, both metal ions stabilize substrate binding and formation of the transition state. In addition, a lysine side chain contributes by polarizing the substrate's carbonyl group, and an arginine side chain binds a bicarbonate anion (or carbonate ion) that is in a position to act, at least in PepA, as a general base to deprotonate the zinc‐bound water nucleophile.
Calpain
Authors: Davies Peter L , Campbell Robert L , Moldoveanu Tudor 
Published: April 2006

Abstract

Calpains are intracellular cysteine proteases that participate in Ca
2+
signaling. Some structural information is available for the ubiquitous mammalian isoforms m‐ and μ‐calpain. These 110‐kDa heterodimeric, multidomain enzymes differ in the level of Ca
2+
required for activation. A structural explanation for the Ca
2+
requirement is that the papain‐like active site is not assembled in the Ca
2+
‐free (apo) state. Moreover, the circular arrangement of domains appears to constrain the two protease core domains from assembling into an active conformation. Ca
2+
binding to the two penta–EF‐hand domains and to a C2‐like domain flanking the protease core may release these constraints. However, active site assembly requires the cooperative binding of Ca
2+
to two non–EF‐hand sites, one on each of the catalytic domains. These novel Ca
2+
binding sites appear to be an evolutionary addition to the papain‐like protease core. Thus, Ca
2+
acts at several different levels, at different sites, to tightly control the activity of this potent protease within the cell.
Parvalbumin
Authors: Nakayama Susumu , Kawasaki Hiroshi , Kretsinger Robert H 
Published: April 2006

AbstractParvalbumin was the first EF‐hand protein to have been characterized and to have its crystal structure determined. This prototype consists of an α‐helix E (extended forefinger of a clenched right hand), loop around the Ca2+ion (clenched middle finger), and α‐helix F (extended thumb). Parvalbumin has provided a reference point for the analyses of 76 other subfamilies of proteins that contain 2 to 12 EF‐hands. Most, but not all, EF‐hands bind calcium. The Ca2+ion is almost always coordinated by seven oxygen atoms arranged in an approximate pentagonal bipyramid; usually one of the ligands is a carboxylate group that coordinates calcium with both its oxygen atoms. The affinities of EF‐hands for calcium range from pKd(Ca2+) 6 to 8. The dissociation constant of parvalbumin for calcium (Kd ∼ 10−8 M) reflects one of the highest affinities of all the EF‐hand proteins. All, or most, of the EF‐hand proteins bind calcium ∼104.0more strongly than they bind the six‐coordinate magnesium. Most of this difference in affinity derives from the ∼103.4greateronrate for calcium, which in turn derives from its faster dehydration rate. Parvalbumin functions in fast, white, skeletal muscle to soak up messenger calcium following a stimulus, thereby facilitating rapid relaxation. Whether it has an analogous function in neurons, thymus, or other tissues remains to be demonstrated. Most EF‐hand proteins change conformation upon binding calcium, thereby transducing the information content of a pulse of cytosolic messenger Ca2+ions. Although the binding of calcium to the two EF‐hands of monomeric parvalbumin is not (or only very weakly) cooperative, as is the case for other EF‐hand proteins, the interaction of a pair of EF‐hands is essential for the stability of these proteins. The angle between the two helices (E and F) of a single EF‐hand as well as the contact between the pair of EF‐hands is usually moreopenfollowing binding of calcium, thereby exposing hydrophobic side chains. However, a survey of the known structures of all known EF‐hands proteins does not reveal a bimodalclosed, openset of conformations reflecting either binding of calcium and/or binding of targets for those EF‐hand proteins involved in information transduction.
Membrane Binding
C
2‐Like Domains
Authors: Verdaguer Nuria , Corbalán‐García Senena , Ochoa Wendy F , Gómez‐Fernández Juan Carmelo , Fita Ignacio 
Published: April 2006

Abstract
C2‐domains are independently folded modules, of about 130 residues, found in a large and diverse set of eukaryotic proteins. Many of the best‐characterized C2‐domains are found in proteins involved in membrane trafficking and fusion, such as synaptotagmins or rabphilin, and in signal transduction, such as phospholipases A2 (cPLA2) and C (PLC) or the protein kinase C isoforms (PKCs). All C2‐domains share a common overall fold: a single compact Greek‐key motif organized as an eight‐stranded antiparallel β‐sandwich consisting of a pair of four‐stranded β‐sheets – the A and B sheets – with a long axis of about 50 Å. Connections between β‐strands emerge from the top and bottom of the domain according to the two distinct topologies of C2‐domains. In topology I (the S family), the first β‐strand occupies the same structural position as the eighth β‐strand of topology II (the P family), which shifts in a circular permutation the order of homologous strands in the primary structure. The structural information defines adjacent calcium binding sites within a broad acidic cleft that contains highly conserved acidic residues. These provide most of the oxygen atoms that coordinate with the calcium ions. The present work will focus on the wealth of functional and structural information, which is being obtained at an exponential pace, on the membrane‐binding C2‐domains that require calcium.
Cytochrome

c

553
Authors: Nakagawa Atsushi 
Published: April 2006

Abstract

Cytochrome
c
553
in sulfate‐reducing bacteria,
Desulfovibrio vulgaris
, receives electrons from formate dehydrogenase and lactate dehydrogenase, and then transfers them to cytochrome
c
3
. Cytochrome
c
553
is a monoheme
c
‐type cytochrome with an absorption band at 553 nm in the reduced form and is the smallest
c
‐type cytochrome with a molecular weight of 9000. Its three‐dimensional structure has been determined by both x‐ray crystallography and NMR.
Nine‐Heme Cytochrome

c
Authors: Arménia Carrondo Maria , Soares Cláudio M , Matias Pedro M 
Published: April 2006

Abstract

Nine heme cytochrome c (9Hcc) is a monomeric multi‐heme cytochrome c found in the sulfate‐reducing bacteria of

Desulfovibrio desulfuricans

(Dd) ATCC 27774 and

Desulfovibrio desulfuricans

Essex 6. The polypeptide chain comprises 296 residues and wraps around nine hemes of type‐c that bind the polypeptide chain through thioether bridges to cysteine residues. This represents the first known structure of a multi‐heme cytochrome where copies of a tetra‐heme cytochrome
c
3
‐like fold are present in the same polypeptide chain.

The high homology between 9Hcc and the C‐terminal region of

Desulfovibrio vulgaris

Hildenborough (DvH) Hmc, as well as the presence of the
9Hcc
gene within an operon similar to that of the DvH Hmc, strongly support the proposal that 9Hcc is the high‐molecular‐weight cytochrome of Dd. Several
in vitro
studies, as well as our crystallographic and modeling studies suggest that cytochrome
c
3
is the mediator between the [NiFe] hydrogenase and 9Hcc in Dd.
b‐Type Cytochrome Electron Carriers: Cytochromesb562andb5, and Flavocytochromeb2
Authors: Mathews F Scott 
Published: April 2006

Abstractb‐Type cytochromes form a class of proteins that contain a heme (iron‐protoporphorin IX) bound non‐covalently to its polypeptide chain with two of its side chains coordinated to the iron. One of these side chains is always histidine and the other can be histidine or methionine. Cytochromes b5and b562are simple mono‐domain proteins that contain heme as the only prosthetic group and histidine and methionine, respectively, as the second heme ligand. Flavocytochrome b2also contains histidine as the second heme ligand, but contains a second prosthetic group, flavin mononucleotide (FMN), that resides in a separate domain. Cytochromes b5and b562each mediate intracellular electron transfer between redox partners, the former within the endoplasmic reticulum of mammalian cells and the latter within bacteria. Flavocytochrome b2catalyzes the oxidation of lactic acid within yeast mitochondria, with the cytochrome domain mediating electron transfer from substrate‐reduced FMN to exogenous cytochrome c. The structural, electrochemical, and catalytic properties of these three proteins are presented, along with the results of mutagenesis.
Prostaglandin EndoperoxideH2Synthases‐1 and ‐2
Authors: Michael Garavito R 
Published: April 2006

AbstractThe prostaglandin endoperoxide H2synthase (PGHS) isozymes 1 and 2 are membrane bound, heme‐dependent enzymes that catalyze the committed step in the conversion of polyunsaturated fatty acids to prostanoids and thromboxanes. The PGHS isozymes, which are also known as cyclooxygenases, produce prostaglandin H2in two sequential enzymatic steps – a bis‐oxygenase (cyclooxygenase) reaction generates prostaglandin G2from arachidonic acid and a hydroperoxidase reaction creates the final product, prostaglandin H2. The PGHS isozymes are also the primary targets of nonsteroidal anti‐inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, and recent pharmacological research efforts have led to the development of isoform selective drugs like Celebrex® and Vioxx®. In this chapter, we discuss the biochemistry, enzymology, and the structural biology of the PGHS isozymes and their relevance to prostanoid physiology and NSAID pharmacology.
Succinate:Quinone Oxidoreductases
Authors: Lancaster C Roy D 
Published: April 2006

AbstractSuccinate:quinone oxidoreductases encompass the succinate:quinone reductase (SQR) enzymes of aerobic respiration (respiratory complex II) and the quinol:fumarate reductase (QFR) enzymes of anaerobic respiration. These enzymes couple the two‐electron oxidation of succinate to fumarate to the two‐electron reduction of quinone to hydroquinone (quinol), and also catalyse the reverse reaction, the reduction of fumarate by quinol. Members of the superfamily are composed of two hydrophilic subunits, a large flavoprotein subunit A and a smaller subunit B containing three iron–sulfur centers, and one large subunit C or two small subunits C and D hydrophobic polypeptides that are integral membrane proteins and bind two, one, or no hemebgroups. On the basis of the available crystal structures of members of the superfamily, structural and functional aspects of succinate:quinone oxidoreductases are comprehensively discussed.
Cytochromecd1Nitrite Reductase
Authors: Allen James WA , Ferguson Stuart J , Fülöp Vilmos 
Published: April 2006

AbstractCytochromecd1catalyzes the one‐electron reduction of nitrite (NO2−) to nitric oxide and water. It is isolated from many bacteria, which respire by the process of denitrification.In vitro,cd1is also an oxidase and a hydroxylamine reductase. Each monomer of the dimeric enzyme contains onec‐type cytochrome center, which accepts electrons from donor proteins, and oned1heme, which is the active site and is unique to this class of enzymes. High‐resolution X‐ray structures have shown that in the oxidized forms, when isolated, the axial coordination of the hemes differs between the best‐studied cytochromescd1, the enzymes fromParacoccus pantotrophusandPseudomonas aeruginosa. Upon reduction, theP. pantotrophusenzyme undergoes a major and unprecedented conformational change and adopts the same heme coordinations as that of the reducedP. aeruginosacd1. The structural differences between the enzymes from these two sources are reflected in their biochemical, electron transfer, and spectroscopic properties.