bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exoenzyme C3 (Clostridium botulinum)
Authors: Lemichez E , Boquet P , Popoff M R 
Published: November 2023

Abstract
ADP-ribosylating toxins have proved to be valuable tools for studying their target proteins. The targets generally suffer important changes in function upon modification, and they become labelled when radioactive NAD is used. In this respect C3 has proved to be extremely useful in understanding the physiological role of the small GTP-binding protein Rho (Narumiya and Morii 1993; Hall 1994).
Introduction
Authors: Murphy J R 
Published: November 2023

Abstract
During the past decade there has been an enormous increase in our understanding of the structure-function relationships and molecular mechanism of action of many of the toxins that affect protein synthesis. The toxins considered in this section inhibit eukaryotic cellular protein synthesis either by the NAO+ dependent adenosine diphosphate ribosylation of elongation factor 2 or function as an N-glycosidase to remove adenine 4324 (A4324) from 28S rRNA which leads to an impaired ability of the ribosome to bind elongation factors. The X-ray crystal structure of ricin (Montfort et al. 1987; Rutenber et al. 1991), Pseudomonas exotoxin A (Allured et al. 1986), diphtheria toxin (Choe et al. 1992; Bennett et al. 1994), and Shiga toxin (Fraser et al. 1994) have been solved. Both crystallographic and biochemical genetic analysis have led to a detailed understanding of the adenosine diphosphate ribosyltransferase activity of diphtheria toxin and Pseudomonas exotoxin A (Collier 1990; Wick and lglewski 1990) and the N-glycosidase activity of ricin, Shiga toxin, and the plant derived ribosome-inactivating proteins (Jimenez and Vasquez 1985; Stirpe and Barbieri 1986). Most all of these toxins have been highly purified, and their respective genes have been cloned and sequenced. In addition, many of their respective enzymatically active fragments or chains have been employed in the assembly of immunotoxins by the chemical crosslinking of the catalytic domains of either a bacterial or plant toxin to a monoclonal antibody (Ghetie and Vitetta 1994). More recently, recombinant DNA and protein engineering methods have been used to create chimeric genes in which the native receptor binding domain of either diphtheria toxin or Pseudomonas exotoxin A have been genetically substituted with one of a variety of genes encoding a polypeptide ligand that is directed toward a specific cell surface receptor or antigenic determinant on the target cell surface (for reviews see Kreitman and Pastan 1994; Murphy et al. 1995).
Shiga toxins (Shigella dysenteriae serotype 1, Escherichia coli)
Authors: Melton-Cels A R , O’Brien A 
Published: November 2023

Abstract
The Shiga toxins (also known as verotoxins) comprise a family of toxins that inhibit protein synthesis in intoxicated cells (for reviews see O’Brien and Holmes 1987; O’Brien et al. 1992; Obrig 1994). The holotoxin consists of an A polypeptide (Mr 32 000) that has N-glycosidase activity which removes a single adenine residue from the 28 S rRNA (the same mode of action is found in the plant toxin ricin), and a pentamer of B polypeptides (Mr 7700 each) that confers specificity for the eukaryotic cell receptor, globotriaosylceramide or Gb3 (Lingwood 1993). Toxin entry into the eukaryotic cell occurs via receptor-mediated endocytosis with subsequent routing of the toxin from the transgolgi through the endoplasmic reticulum to the cytosol (Sandvig and Deurs 1994). The A subunit contains a trypsin cleavage site near the (-terminus, but the importance of this nicking site for cytotoxicity is still under investigation.
Ricin (Ricinus communis)
Authors: Sandvig K 
Published: November 2023

Abstract
Ricin is synthesized in the endosperm cells of Ricinus communis seeds, and there are various isoforms with molecular weights of 63-66 kDa. The molecule is glycosylated (for review, see Barbieri et al. 1993; Lord et al. 1994). The ricin gene codes for a preprotoxin molecule which is processed in the plant (preproricin D: 576 amino acids, GenBank accession no. X52908). The leader sequence of ricin D has 35 amino acid residues, and the interchain linker between the two chains has 12 amino acids (Lord et al. 1994). The mature form of ricin D (Fig. 1) has an A-chain with 267 amino acids and a B-chain with 262 residues.
α-Sarcin and related toxins (Aspergillus)
Authors: Gasset M 
Published: November 2023

Abstract
Aspergillins are a family of toxic extracellular fungal ribonucleases displaying a high amino acid sequence homology (Table 1). a-Sarcin, mitogillin, and restrictocin were discovered and characterized as antitumoral agents displaying in vivo cytotoxity (Olson and Goerner 1965; Goldin et al. 1966). However, their clinical use was hampered since they revealed to be too toxic (Roga et al. 1971). Asp fl was recently discovered as an lgE-binding protein involved in the pathogenesis of invasive aspergillosis (Arruda et al. 1990; Lamy et al. 1991).
Anthrax lethal toxin (Bacillus anthracis)
Authors: Hanna P C , Collier R J 
Published: November 2023

Abstract
Anthrax lethal toxin (LeTx) induces shock and sudden death in test animals, mimicking the symptoms of systemic anthrax infections (eppla 1991; Hanna et al. 1993). Bacterial strains lacking either of the two LeTx components are highly attenuated, and immunization against the toxin protects animals from 8. anthracis challenge (Cataldi et al. 1990; Pezard et al. 1991; Turnbull 1991).
Botulinum neurotoxin type C (Clostridium botulinum)
Authors: Herreros J , Blasi J 
Published: November 2023

Abstract
Botulinum neurotoxin C (BoNT/C} is one of the seven neurotoxins produced by the anaerobic bacteria Clostridium botulinum, and are responsible for the flaccid paralysis characteristic of botulism. Its structural gene is located on the genome of bacteriophages (GenBank accession number X53751), which produce a 150 kDa protein of 1290 amino acids (Swiss-Prot accession number P18640) responsible for the neurotoxigenicity of the strain (Eklund et al. 1989).
μ-Conotoxins (Conus geographus)
Authors: Cruz L J 
Published: November 2023

Abstract
μ-Conotoxins are small basic peptides that inhibit the action potential of skeletal muscle by blocking voltagegated sodium channels (Cruz et al. 1985; Gray et al. 1988). Three major homologues and four minor under hydroxylated forms (see Table 1) have been found in the venom of the most dangerous Conus species, C. geographus (Sato et al. 1983; Cruz et al. 1985). The peptides contain 22 amino acid residues including three hydroxyprolines and six cysteines. The presence of several Lys and Arg residues renders μ-conotoxins highly positive: a charge of +6 in GIIIA and +7 in GIIIB and GIIIC. The major peptide is μ-conotoxin GIIIA or geographutoxin I; μ-conotoxin GIIIB (geographutoxin II) and μ-conotoxin GIIIC occur in smaller amounts. The minor forms appear to be the post-translational processing intermediates of GIIIA and GIIIB, which contain proline instead of hydroxyproline at either position 6 or 7.
Anemone toxins (type II)
Authors: Norton R S 
Published: November 2023

Abstract
Sea anemones produce a family of closely related cardioactive and neurotoxic polypeptides having molecular masses of approximately 5 kDa. These toxins have been classified into two groups, type I toxins from the family Actiniidae (Actinia sp. and Anthopleura sp.) and type II toxins from the family Stichodactylidae (Heteractis sp. and Stichodactyla sp.) (Kem 1988). The amino acid sequences of several type II toxins are shown in Fig. 1.These two classes of toxin are similar with respect to the locations of their disulfide bridges and a number of residues thought to play a role in biological activity or maintenance of the tertiary structure, but they are distinguishable on the basis of sequence similarity (&gt; 60 per cent within each type, but &lt; 30 per cent between the two types) and immunological crossreactivity. Some of the distinguishing features of the type II toxins are a triplet of acidic residues at positions 6-8, an extension of basic residues at the (-terminus, and the substitution of acidic or polar residues for the aromatic residues at positions 22 and 42 in the type I toxins. Other toxins have been isolated which do not fall neatly into either class.
Sea anemone potassium channel toxins
Authors: Pennington M W , Kem W R , Karlsson E 
Published: November 2023

Abstract
During screening for dendrotoxin-like compounds in marine organisms, extracts of several sea anemones were found to inhibit the binding of 125I-dendrotoxin I, a probe for voltage dependent potassium channels, to rat brain synaptosomal membranes (Harvey et al. 1991; Karlsson et al. 1991). Two toxins were later isolated from Carib¬ bean sea anemones, ShK toxin from Stichodactyla helianthus (Karlsson et al. 1992; Aneiros et al. 1993; Castaneda et al. 1995) and BgK toxin from Bunodosoma granulifera (Karlsson et al. 1992). More recently, another toxin has been isolated from Anemonia sulcata, which we refer to here as AsK toxin (Schweitz et al. 1995). These toxins are known to block voltage-dependent potassium channels.
ω-Agatoxins (Agelenopsis aperta)
Authors: Norris T M , Adams M E 
Published: November 2023

Abstract
ω-Aga-lA (7791 Da) is a 69 amino acid (Table 1) heterodimeric peptide composed of a 66 amino acid major chain and a three amino acid minor chain connected by a disulfide bond (Adams et al. 1990; Santos et al. 1992). The major chain contains four internal disulfide bonds. N-terminal amino acid sequences of ω-Aga-1B and IC indicate that they have related structures (Adams et al. 1990). ω-Aga-lA blocks presynaptic calcium channels at the insect neuromuscular junction and calcium action potentials in insect neurosecretory neurons (Bindokas and Adams 1989; Bindokas et al. 1991). Calcium channel currents in rat dorsal root ganglion neurons are also blocked by ω-Aga-lA (Scott et al. 1990).
Taicatoxin (Oxyuranus scutelatus scutelatus)
Authors: possani L D 
Published: November 2023

Abstract
Taicatoxin (TCX) is a complex oligomeric toxin isolated from the venom of the Australian taipan snake Oxyuranus scutelatus scutelatus. It contains three different active components: an a-neurotoxin-like peptide with a mol. wt of 8 kDa, a phospholipase of mol. wt 16 kDa, and a serine protease inhibitor of mol. wt 7 kDa, joined by noncovalent bonds, at an approximate stoichiometry of 1:1:4, respectively. The most active form is composed of these three peptides, although the phospholipase and the neurotoxin-like peptides are toxic by themselves.
α-Cobratoxin (Naja kaouthia)
Authors: Menez A , Servent D 
Published: November 2023

Abstract
The cobras (Elapidae) form a group of snakes that are wide-spread in Africa and Asia (Harding and Welsh 1980). Their venoms contain various types of toxins to subdue prey. These include toxins, called α-neurotoxins or curaremimetic toxins, that recognize the nicotinic acetylcholine receptors (AchRs), causing flaccid paralysis and hence respiratory failure. They are basic proteins classified as long-chain toxins with 66-72 amino acids and 4/5 disulfides, and short-chain toxins with 60-62 amino acids and four disulfides. The snake Naja kaouthia, previously named Naja naja kaouthia or Naja naja siamensis, is largely distributed in India, Bangladesh, Nepal, Burma, Thailand, Vietnam, and south-west China.
Helothermine (Heloderma horridum horridum)
Authors: Becerril B , Pardo L , Possani L D 
Published: November 2023

Abstract
Helothermine (HLTX) is a toxin isolated from the venom of the Mexican beaded lizard He/oderma horridum horridum (Mochca-Morales et al. 1990). It is synthesized as a single chain polypeptide precursor of 242 amino acid residues including a signal peptide of 19 residues (Morrissette et al. 1995). One of its remarkable characteristics (mature toxin of 223 residues and a mol. wt of 25.5 kDa) is the high content of cysteine residues (16, with 10 of them located within the last 54 carboxy-terminal residues). It has an isoelectric point (pl) of 6.8, and among the observed effects in mice injected with this toxin are: lethargy, partial paralysis of rear limbs, and lowering of body temperature (Mochca-Morales et al. 1990). This hypothermic effect gave us the idea to call it helothermine, from Heloderma and hypothermic.
Palytoxin (Corals of the spp. Palythoa)
Authors: Habermann E 
Published: November 2023

Abstract
Palytoxin (MW about 2670) occurs in several Pa/ythoa species. It is unknown whether they produce the toxin or acquire it from symbiotic organisms. The heat-resistant toxin is also found in crabs and fish, which possibly take it up with their food. Its unique structure (Cha et al. 1982) has been synthesized (Armstrong et al. 1989) and its stereochemistry (Moore et al. 1982) determined (Fig.1).
α-Actinins
Authors: Flood David R Critchley,Geoffrey 
Published: November 2023

Abstract
α-Actinin displays homology with erythroid and non-erythroid spectrins, dystrophin, and utrophin. These proteins all share a similar domain structure, with an N-terminal actin-binding domain, a variable number of triple α-helical spectrin-like repeats, and a pair of C-terminal EF hands. The actin-binding domain of α-actinin is homologous to that in filamin, fimbrin, and ABP 120, and there is a more limited match with the N-terminal domain of calponin.
IFAP 300
Authors: Skalli Omar 
Published: November 2023

Abstract
IFAP 300 is a 300 kDa intermediate filament-associated protein which, in vitro, binds to and cross-links intermediate filaments (IF). In fibroblasts, the distribution of IFAP 300 is similar to that of vimentin IF, while in epithelial cells IFAP 300 associates with keratin IF at the site where they anchor into desmosomes and hemidesmosomes. This suggests that IFAP 300 serves cell-type specific functions, such as organizing IF into a three-dimensional network in fibroblasts, and connecting IF to desmosomes and hemidesmosomes in epithelial cells.
Kinesin, bipolar
Authors: Ray Krishanu , Goldstein Lawrence S B 
Published: November 2023

Abstract
Members of the Kin N bipolar class of kinesin motors have been identified from a variety of species including yeasts, Aspergillus, Drosophila, and Xenopus. All of these proteins have the motor domain at the N terminus, associate with spindle microtubules during mitosis, and appear to be involved in centrosome movement and spindle formation. A native Drosophila homologue (KRP130) has been purified as a bipolar homotetramer and moves towards the plus end of microtubules.
Kinesin, orphan
Authors: Philp Alastair Valentine , Goldstein Lawrence S B 
Published: November 2023

Abstract
‘Orphan’ kinesin refers to members of the kinesin superfamily which do not align closely to other kinesin classes based upon their motor domain sequences. Here, four kinesin orphans CENP-E, MKLP-1, nod, and kid are described, all of which appear to have important functions in chromosome segregation during mitosis or meiosis. Proposed sites of action for each of these four proteins are shown in Fig. 1.
Myosin heavy chain kinases
Authors: Egelhoff Thomas T , Coté Graham P 
Published: November 2023

Abstract
Several classes of myosin heavy chain (MHC) kinases have been identified in various systems. For this review, we will focus on two distinct groups of myosin kinases, myosin II heavy chain kinase A (MHCK A} from Dictyostelium and related enzymes, and myosin I heavy chain kinase (MIHCK), identified in Dictyostelium and other systems. The interactions of broad specificity kinases such as protein kinase C (PKC) and CAM kinase ti with myosin have been reviewed elsewhere1 and will not be addressed here. Another myosin kinase not discussed here is the ‘PKC-MHCK’ from Dictyostelium, which appears to contain a catalytic domain related to PKC and a distinct catalytic domain related to diacylglycerol kinases. This latter enzyme appears to participate in myosin localization control during Dictyostelium chemotaxis.
Kinectin
Authors: McGoldrick Carol , Sheetz Michael 
Published: November 2023

Abstract
Kinectin is a protein found on the surface of vesicles that interacts with the intracellular motor kinesin. Monoclonal antibodies directed against kinectin inhibit microtubule-based motility in vitro. By linking microsomal membranes to the microtubule-motor system via its interaction with kinesin, kinectin may be responsible for the maintenance of organelle location and function within the cell.
Comitin
Authors: Noegel Angelika A 
Published: November 2023

Abstract
Comitin was first purified from Dictyostelium discoideum membranes based on its ability to bind to radiolabelled F- and G-actin. It is a highly basic protein (p/ = 9.6) encompassing 185 amino acids with a calculated molecular mass of 20 697 Da and does not contain a transmembrane domain nor extended hydrophobic regions.
Gephyrin
Authors: Kirsch Joachim , Betz Heinrich 
Published: November 2023

Abstract
Gephyrin was originally identified as a peripheral membrane protein of 93 kDa, which copurifies with the -mammalian inhibitory glycine receptor upon affinity chromatography.8-10 lmmunoelectron microscopy locates gephyrin to the cytoplasmic face of glycinergic postsynaptic membranes in spinal cord, brain, and retina.
α-Catenin
Authors: Kemler Rolf 
Published: November 2023

Abstract
Originally a-catenin was identified in immunoprecipitation experiments as a 102 kDa protein coprecipitating with antibodies against E-cadherin. Primary structure analysis of α-catenin revealed homology to vinculin, a protein first described as a component of focal adhesions, and suggested the existence of a vinculin-related family of proteins that mediates cytoplasmic anchorage of cell—cell and cell-substrate adhesion molecules to the cytoskeleton. There are three regions of homology, an N-terminal, a central and a C-terminal domain; in vinculin these domains have been shown to contain binding sites for talin, α-actinin, paxillin, and actin. Initial biochemical analysis has already indicated that α-catenin represents the key component for linking the cadherin adhesion complex to the actin filament network.
Drosophila actin-associated proteins: Bottleneck, Nullo, and Serendipity-α
Authors: Hunter C , Wieschaus E 
Published: November 2023

Abstract
Bottleneck (Bnk) is a 303 amino acid basic (p/ = 10.7) protein, with no striking motifs or homologies. It is expressed during early stages of Drosophila embryogenesis, when it is required during cellularization.1 Prior to cellularization, Bnk protein is found at the surface of the embryo, and localizes to the transient furrows formed during mitosis. In the early stages of cellularization, Bnk colocalizes with the hexagonal actin array which forms at the cellularization front. During this stage, weak cytoplasmic staining is also detectable. Bnk protein is lost from the cellularization front as the actin network rearranges to form an array of rings during the late stages of cellularization. No Bnk protein is detectable by the completion of cellularization.
Hisactophilin
Authors: Schleicher Michael 
Published: November 2023

Abstract
Hisactophilin was detected by the gel overlay technique with iodinated actin using a Dictyostelium extract that was enriched in plasma membranes. About 50 per cent of hisactophilin molecules are bound to the inner surface of the plasma membrane, the other half is found in the cytoplasm. The binding of the protein to F-actin is pH dependent, which is in good agreement with the peculiar amino acid sequences that contain more than 30 mol per cent of histidine residues.
Small actin cross-linking proteins
Authors: Fechheimer Marcus 
Published: November 2023

Abstract
Small actin cross-linking proteins are polypeptides with Mr &lt;35 000 that cross-fink actin filaments into either isotropic (gel) or anisotropic (bundle) arrays. These proteins are found in Dictyostefium and Physarum as well as in higher eukaryotes. Localization in the cortical cytoskeleton, phagocytic cup, cleavage furrow, and cell contact sites suggests a general role in control of actin filament arrays. Initial results from gene disruption experiments in Dictyostelium suggests partial redundancy among distinct highly conserved families of actin cross-linking proteins.
Talin
Authors: Critchley David R 
Published: November 2023

Abstract
Talin is a high molecular weight protein localized in adherens-type junctions with the extracellular matrix (ECM), although it is also localized at the junctions between T-he/per and antigen presenting cells. Ta/in binds in vitro to the cytoplasmic domains of the integrin family of extracellular matrix receptors, to vinculin, actin, and the protein tyrosine kinase pp 125FAK.It has been proposed to be one of several proteins linking actin filament bundles to the cytoplasmic face of integrins.
Thymosin β4
Authors: Safer Daniel , Nachmias Vivianne T 
Published: November 2023

Abstract
There is good agreement that increasing T,β4 by microinjection or by transient transfection leads to disassembly of stress fibre bundles in NRK, PtK2, and CV1 cells (see Fig. 1 for a living PtK2 cell), and micro-injection at high concentrations also leads to disappearance of submembranous F-actin and relaxation of the cytokinetic furrow,15 This is what would be expected if the added β4 thymosin were acting in vivo to further sequester G-actin.
Transgelin
Authors: Lawson Durward 
Published: November 2023

Abstract
Transgelin (Tg) is a transformation and shape-change sensitive actin-associated protein found uniformly distributed on actin filament bundles in normal mesenchymal cells. Tg is evolutionarily conserved as far back as yeast but is absent in erythrocytes, skeletal muscle, motile cells such as lymphocytes, and transformed mesenchymal cells.
Tropomodulin
Authors: Fowler Velia M , Conley Catharine A 
Published: November 2023

Abstract
Tropomodulin (Tmod) is a ∼40 kDa tropomyosin- and actin-binding protein that is associated with the slow growing (pointed) ends of stable, tropomyosin-coated actin filaments in muscle and non-muscle cells. In vitro and in vivo data indicate that Tmod functions to cap the pointed ends of tropomyosin-actin filaments and prevent them from growing or shrinking. In vertebrates, at least three Tmod isotypes and one Tmod-related protein exist which are expressed in a tissue-specific and developmentally regulated fashion. Tmod is a member of a new and rapidly growing family of related proteins with representatives in vertebrates, flies, and worms.
Troponin
Authors: Gergely John , Grabarek Zenon , Tao Terence 
Published: November 2023

Abstract
Troponin (Tn) (for reviews see refs 1-6) is a complex of three subunits: troponin C (TnC), troponin I (Tnl), and troponin T (TnT); together with tropomyosin (TM) it constitutes the Ca2+- dependent regulatory machinery located in the actin filaments of striated muscle. The binding of Ca2+, released in vivo from the sarcoplasmic reticulum upon stimulation of the muscle, to TnC induces conformational change in that subunit, and the effect is transmitted to the other thin filament components. This results in the activation of actomyosin ATPase and, in vivo, force development and shortening of muscle fibres.
α/β-Tubulins
Authors: Caplow Michael , Nogales, Eva , Downing Kenneth H 
Published: November 2023

Abstract
Microtubule protein refers to the mixture of tubulin and proteins that bind to microtubules (MAPs) and copurify with tubulin.
There is no clear homology between tubulin and any known eukaryotic protein, but there is limited sequence homology with bacterial FtsZ, a protein that assembles into protofilament-like structures in vitro.
Tubulin-specific chaperones
Authors: Lewis Sally A , Cowan Nicholas J 
Published: November 2023

Abstract
Tubulin-specific chaperone A has also been termed p14.11 Homologues of chaperones A (RBL2), 12 B (ALF1), 8 D (CIN1), 13 and E (PAC2)14 exist in S. cerevisiae. There is no discernable homologue of chaperone C in S. cerevisiae, although homologues of this chaperone exist in distantly related eukaryotes (e.g. Arabidopsis, C. elegans).