Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Solution of thrombosthenin, the contractile protein complex isolated from pig platelets, have been studied by analytical ultracentrifugation and zone sedimentation in sucrose density gradients. Freshly prepared thrombosthenin in 0.6 M KCl shows a prominent peak in the ultracentrifuge with S degrees 20w about 5.5 and higher molecular weight aggregates (greater than 100S) sedimenting quickly to the bottom of the cell. Short term storage of high ionic strength solutions of thrombosthenin induces actomyosin-like gel formation and these gels dissociate with ATP and Mg2+ ions into two components of S degrees 20w 8.0 and S degrees 20w50. The supernatant, after actomyosin gel removal, contains only the S degrees 20w5.5 protein. From results of Ca2+ ATPase activity measurements and SDS polyacrylamide gel electrophoretic mobilities of dissociated thrombosthenin separated into fractions in sucrose density gradients, it is concluded that the S degrees20w5.5 protein species is the myosin-like protein of thrombosthenin. The S degrees 20w8.0 protein is not fibrinogen but also has myosin-like properties and is believed to be myosin dimer. Species of higher S values seen in the presence of ATP and Mg2+ in the analytical ultracentrifuge and located in the higher density zones of the sucrose gradients all gave in SDS polyacrylamide gel electrophoresis a single band of molecular weight 46-47,000 daltons. These subunit proteins appear to be derived from a range of polymeric variants of the F-actin-like protein of the contractile complex. All these higher density F-actin-like proteins readily form superprecipitates and display syneresis when combined with rabbit skeletal muscle myosin or platelet myosin. They are also all capable of conferring upon these two myosins a Mg2+ activated ATPase activity. It is suggested that in thrombosthenin solutions a myosin monomer-dimer equilibrium state exists which can be directionally influenced by a number of factors. The coexistence in the solution of F-actin and Mg2+ ATP, for example, increases the propensity of the myosin-like protein to form the higher molecular weight aggregate. Such aggregation may be the initiating mechanism for the intracellular organization of the thick filaments of the actomyosin complex, preparatory to a contractile event.
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PMID:Platelet contractile proteins: separation and characterization of the actin and myosin-like components. 12 96

The plain synaptic vesicle and the ocated vesicle fractions were isolated from rat brains, and the ATPase [EC 3.6.1.3] activities were characterized in terms of ionic effects, drug effects, and protein components. Coated vesicle fraction contained three times as much actomysin-like proteins as plain vesicle fraction, although both fractions had an identical ratio of actin-like protein to myosin-like protein. The ATPases of these two fractions were activated by both Mg2+ and Ca2+, and, in the presence of either of the cations, were inhibited by KCl. Reserpine activated plain vesicle ATPase only in the presence of Cl-. Colchicine and vinblastine inhibited coated vesicle ATPase only. The results are consistent with the view that actomyosin-like proteins are involved in the synaptic retrieval process.
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PMID:Characterization of ATPases of plain synaptic vesicle and coated vesicle fractions isolated from rat brains. 13 97

Myosin-like protein was obtained from E. coli by extraction with a sucrose solution and by precipitation with rabbit skeletal actin. The preparation of E. coli myosin-like protein looked very similar, in the sodium dodecyl sulfate-gel electrophoretic pattern, to that of rabbit skeletal myosin. The myosin-like protein was able to reversibly bind to rabbit actin. It had the activities of EDTA-, Ca-, and Mg-ATPases. The product in the EDTA-ATPase reaction catalyzed by the myosin-like protein was identified as ADP by ion exchange chromatography. The Mg-ATPase activity of E. coli myosin-like protein was activated by either rabbit actin or E. coli actin-like protein though the activation was much stronger by the latter. However, the myosin-like protein did not exhibit superprecipitation either with rabbit actin or with E. coli actin-like protein. Actin-like protein was also obtained from E. coli by essentially the same procedures as those described for preparation of rabbit skeletal actin. E. coli actin-like protein was capable of activating Mg-ATPase of rabbit myosin, and also of superprecipitation with rabbit myosin. Extraction from both the whole cells and the membrane fraction of E. coli strongly suggested that the myosin-like protein and the actin-like protein are both localized in the membrane fraction rather than in the cytoplasmic fraction.
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PMID:Myosin-like protein and actin-like protein from Escherichia coli K12 C600. 14 24

The actin-like protein with a molecular weight of 42 kDa was obtained from the preparation of freshly isolated mitochondria of the rat liver using the method of immobilized DNAse affinity chromatography. The inhibitory ability of the isolated protein with respect to pancreatic DNAse I was the same as that of muscular actin. The native structure of the mitochondria protein is confirmed by the data of spectral analysis and its ability to globular-fibrillar transformation with an increased ionic strength of the solution. The polymerization ability as well as a stimulating effect of the actin-like protein of mitochondria on the ATPase activity of myosin is much less pronounced as compared to actin of skeletal muscles.
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PMID:[Biochemical characteristics of functionally active actin-like protein from liver mitochondria]. 293 81

The distribution, ultrastructure, and chemistry of microfilaments in cultured chick embryo fibroblasts were studied by thin sectioning of flat-embedded untreated and glycerol-extracted cells, histochemical and immunological electron microscopic procedures, and the negative staining of cells cultured on electron microscopic grids. In these cultured cells, the microfilaments are arranged into thick bundles that are disposed longitudinally and in looser arrangements in the fusiform-shaped cells. In the latter case, they are concentrated along the margins of the flattened cell, on the dorsal surface, and particularly at the ends of the cell and its ventral surface, where contact is made with the plastic dish or with other cells. Extracellular filaments, presumably originating from within the cell, are found at these points of contact. The microfilaments are composed in part of an actin-like protein. These filaments are between 70 and 90 A in diameter, they are stable in 50% glycerol, they have an endogenous ATPase (myosin-like?) associated with them, they bind rabbit muscle heavy meromyosin, and they specifically bind antibody directed against isolated actin-like protein. In the cultured chick embryo fibroblasts, the microfilaments are essential for the establishment and maintenance of form, and they are probably critical elements for adhesion and motility. The microfilaments might also serve as stabilizers of intramembranous particle fluidity.
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PMID:The distribution, ultrastructure, and chemistry of microfilaments in cultured chick embryo fibroblasts. 426 85

Using affinity chromatography on DNAase I-Sepharose, an actin-like protein was isolated from rat liver mitochondria and purified 60-fold. SDS electrophoresis in polyacrylamide gel revealed that the protein migrated with muscle actin and thus had the molecular weight of 42 000 Da. Evidence for the actin-like nature of the mitochondrial protein could be obtained from the fact that the protein inhibited the activity of pancreatic DNAase I which, similar to the smooth muscle protein, was less conspicuous than that of its muscle counterpart. Unlike striated muscle actin but similar to the smooth muscle protein, the mitochondrial actin weakly stimulated the Mg-ATPase activity of rabbit skeletal muscle myosin. After manyfold washing of the mitochondria with isotonic isolation media, the content of the actin-like protein remained unchanged, which indirectly points to the presence of insignificant cytoplasmic actin contaminations. During isoelectrofocusing, the mitochondrial actin-like protein yielded two forms, i. e., beta- and gamma-isoactins, whose ratio was 8:1. The pI values for the beta- and gamma-isoforms were 5.52 and 5.59, respectively. The identical position of the absorption spectra (260 nm) and fluorescence excitation spectra (around 280 nm) maxima of the actin-like protein and smooth and skeletal muscle actins testify to their homology.
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PMID:[Isolation and characteristics of actin-like proteins in liver mitochondria]. 624 Sep 91

Two dyneins have been isolated from axonemes of Chlamydomonas flagella by a three step procedure consisting of extraction in a high salt containing buffer, hydroxyapatite chromatography and sedimentation in sucrose gradient. A dynein with Mg+2- dependent ATPase activity 6.0 mumole Pi/min/mg, sedimenting at 12.5S was found associated with a polypeptide of molecular weight 310,000. A second dynein with specific activity of 3.7, sedimenting at 10-11S was found associated with a polypeptide of molecular weight 315,000. In their most purified forms, the two dyneins are complexed with nonstoichiometric amounts of four polypeptides ranging in molecular weight between 42,000 and 19,000. The 42,000 component has been identified previously as an actin-like protein. The high molecular weight subunits of both dyneins and two polypeptides of 28,000 and 19,000 molecular weight were found to be phosphorylated by in vivo pulse-labeling with 32P-phosphoric acid. All components of the 12.5S and 10-11S dynein complexes, with the exception of the 19,000 polypeptide, form a subset of polypeptides found to be deficient in pf-23, a chlamydomonas mutant, which is defective for inner arms.
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PMID:Inner arm dyneins from flagella of Chlamydomonas reinhardtii. 646 May 59

FtsZ, a tubulin-like protein with GTPase activity, and FtsA, an actin-like protein with ATPase activity, are two proteins known to play critical roles in the later stages of the bacterial cell cycle. It is well documented that FtsA-FtsZ co-localization at the septum of dividing bacteria is essential for successful cell division in E. coli. We have validated and characterized this interaction by co-expressing FtsA and FtsZ, from both E. coli and S. aureus, in the yeast two-hybrid system. We demonstrate for the first time a specific association between S. aureus FtsA and FtsZ proteins and self interaction of S. aureus FtsZ. These observations are consistent with the conserved role of FtsA and FtsZ in bacterial cell division. Using deletion mutagenesis, we have shown that a highly conserved motif as small as 10 residues in the extreme C-terminus of S. aureus FtsZ is critical for the interaction with FtsA. Further dissection of this motif by alanine scanning mutagenesis showed that Phe376 likely plays a major role in the FtsA-FtsZ interaction. This work has important implications for the design of antagonists and agonists of the FtsA-FtsZ interaction as such agents could provide a novel approach for tackling multi-resistant Gram positive pathogens.
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PMID:A conserved residue at the extreme C-terminus of FtsZ is critical for the FtsA-FtsZ interaction in Staphylococcus aureus. 1075 35

The antigenic structures of the haemotrophic Mycoplasma suis, an epicellular parasite of porcine erythrocytes, are largely unknown due to its unculturability. In this study, serological proteome and mass spectrometry analyses allowed the characterization of M. suis proteins targeted by the porcine antibody response: two proteins with characteristics of heat shock proteins, two proteins with characteristics of glycolytic enzymes, a RNA helicase- and an actin-like protein. The DnaK-like protein of M. suis (HspA1) was further analysed genetically and functionally. Its encoding gene (M. suis a1 gene) is 1.830 bp in size and corresponds to a 67 kDa protein. Immunoelectron microscopy verified the surface accessibility of HspA1 in M. suis. Recombinant HspA1 expressed in Escherichia coli demonstrated ATPase activity and antigenicity in experimentally infected pigs. In conclusion, this first identification and recombinant expression of an antigenic protein of M. suis provides the basis for the development of vaccines and new in vitro diagnostic assays.
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PMID:First identification and functional characterization of an immunogenic protein in unculturable haemotrophic Mycoplasmas (Mycoplasma suis HspA1). 1732 55

A glycosylated arginase acting as a fungal lectin from Peltigera canina is able to produce recruitment of cyanobiont Nostoc cells and their adhesion to the hyphal surface. This implies that the cyanobiont would develop organelles to motility towards the chemoattractant. However when visualized by transmission electron microscopy, Nostoc cells recently isolated from P. canina thallus do not reveal any motile, superficial organelles, although their surface was covered by small spindles and serrated layer related to gliding. The use of S-(3,4-dichlorobenzyl)isothiourea, blebbistatin, phalloidin and latrunculin A provide circumstantial evidence that actin microfilaments rather than MreB, the actin-like protein from prokaryota, and, probably, an ATPase which develops contractile function similar to that of myosin II, are involved in cell motility. These experimental facts, the absence of superficial elements (fimbriae, pili or flagellum) related to cell movement, and the appearance of sunken cells during of after movement verified by scanning electron microscopy, support the hypothesis that the motility of lichen cyanobionts could be achieved by contraction-relaxation episodes of the cytoskeleton induced by fungal lectin act as a chemoattractant.
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PMID:Fungal lectin of Peltigera canina induces chemotropism of compatible Nostoc cells by constriction-relaxation pulses of cyanobiont cytoskeleton. 2189 28


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