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S V Perry

Publications and source records attributed to S V Perry.

At least 19 recordsLinked to original sources
PubMed1992

Binding sites involved in the interaction of actin with the N-terminal region of dystrophin.

Two actin-binding sites have been identified on human dystrophin by proton NMR spectroscopy of synthetic peptides corresponding to defined regions of the polypeptide sequence. These are Actin-Binding Site 1 (ABS1) located at residues 17-26 and Actin-Binding Site 2 (ABS2) in the region of residues 128-156. Using defined fragments of the actin amino acid sequence, ABS1 has been shown to bind to actin in the region represented by residues 83-117 and ABS2 to the C-terminal region represented by residues 350-375. These dystrophin-binding sites lie on the exposed domain in the actin filament.

Actins↗
PubMed1990

Structural study of gizzard caldesmon and its interaction with actin. Binding involves residues of actin also recognised by myosin subfragment 1.

The interaction between actin and caldesmon that is associated with the inhibition of actomyosin ATPase activity in smooth muscle has been studied using 1H-NMR spectroscopy. Binding studies using the intact molecules were complemented by the use of thrombic cleavage fragments of both turkey and chicken gizzard caldesmon as well as defined peptides of actin, in order to investigate the conformational properties of caldesmon and to localise regions of the primary structures that participate in protein-protein contacts. The binding of caldesmon is shown to involve distinct segments on the N-terminal region (residues 1-44) of actin, as previously observed for the inhibitory component of the thin filament of striated muscle, troponin I [Levine et al. (1988) Eur. J. Biochem. 153, 389-397]. The comparable structural properties of these tissue-specific inhibitors of actomyosin ATPase and the similarities in their mode of interaction at the N-terminal region of actin suggest common aspects to the structural mechanism for thin-filament regulation in smooth and striated muscle. Unlike the inhibitory interaction of troponin I, however, the binding of caldesmon to the N-terminal region of actin directly involves groups within residues 20-41 of actin that are also recognised by myosin subfragment 1. The complementary segment of caldesmon has been localised to a 15-kDa thrombic fragment (residues 483-578) derived from the N-terminal portion of a 35-kDa proteolytic cleavage product from the C-terminal of caldesmon whose interaction with actin is modulated by calmodulin. The results are discussed in relation to the calcium-mediated mechanism for thin-filament regulation in smooth and striated muscle.

Actins↗
PubMed1990

The interaction of actin with dystrophin.

Proton NMR spectroscopy of synthetic peptides corresponding to defined regions of human dystrophin has been employed to study the interaction with F-actin. No evidence of interaction with a C-terminal region corresponding to amino acid residues 3429-3440 was obtained. F-actin restricted the mobility of residues 19-27 in a synthetic peptide corresponding to residues 10-32. This suggests that this is a site of F-actin interaction in the intact dystrophin molecule. Identical sequences to that of residues 19-22 in dystrophin, namely Lys-Thr-Phe-Thr are also present in the N-terminal regions of the alpha-actinins implying this is also a site of F-actin interaction with alpha-actinin.

Actins↗
PubMed1979

Calmodulin-binding proteins from brain and other tissues.

The calmodulin contents of rabbit brain, lung, kidney and liver, of bovine aorta and uterus, and of chicken gizzard have been determined. 2. The calmodulin in all of these tissues has been shown to be present in the form of very stable complexes with several other proteins. 3. A calmodulin-binding protein of mol.wt. 22 000 has been purified in high yield from bovine brain. It has been shown to interact with calmodulin and rabbit skeletal-muscle troponin C in a Ca2+-dependent manner. 4. The 22 000-mol.wt. protein inhibits the activation of bovine brain phosphodiesterase by calmodulin, but has very little affect on the activation of myosin light-chain kinase. 5. Calmodulin-binding proteins of mol.wts. 140000, 77000 and 61000 have also been partially purified from rabbit brain by affinity chromatography and have been shown to interact in a Ca2+-dependent manner with calmodulin. 6. The apparent molecular weights of the calmodulin-calmodulin-binding protein complexes, determined by gel filtration in the presence of 6M-urea, have been shown to be similar for most of the mammalian tissues examined. 7. By using 125I-labelled calmodulin, similar complexes have been demonstrated in rabbit skeletal muscle, although they are present at much lower concentrations.

Amino Acids↗
PubMed1979

Distribution of polymorphic forms of troponin components and tropomyosin in skeletal muscle.

Specific antibodies have been used to show that in adult skeletal muscle the slow and fast forms of the components of the troponin complex are located in type I and type II fibres respectively. alpha-Tropomyosin is restricted to type II cells. During development, as a result of changes in innervation and in certain diseased stages, both the slow and fast polymorphic forms of the troponin components are present in the same cell.

Animals↗
PubMed1979

Calmodulin and myosin light-chain kinase of rabbit fast skeletal muscle.

1. It is confirmed that myosin light-chain kinase is a protein of mol.wt. about 80,000 that is inactive in the absence of calmodulin. 2. In the presence of 1 mol of calmodulin/mol of kinase 80-90% of the maximal activity is obtained. 3. Crude preparations of the whole light-chain fraction of rabbit fast-skeletal-muscle myosin contain enough calmodulin to activate the enzyme. A method for the preparation of calmodulin-free P light chain is described. 4. A procedure is described for the isolation of calmodulin from rabbit fast skeletal muscle. 5. Rabbit fast-skeletal-muscle calmodulin is indistinguishable from bovine brain calmodulin in its ability to activate myosin light-chain kinase. The other properties of these two proteins are also very similar. 6. Rabbit fast-skeletal-muscle troponin C was about 10% as effective as calmodulin as activator for myosin light-chain kinase. 7. By chromatography on a Sepharose-calmodulin affinity column evidence was obtained for the formation of a Ca2+-dependent complex between calmodulin and myosin light-chain kinase. 8. Troponin I from rabbit fast skeletal muscle and histone IIAS were phosphorylated by fully activated myosin light-chain kinase at about 1% of the rate of the P light chain.

Animals↗
PubMed1979

Troponin C-like proteins (calmodulins) from mammalian smooth muscle and other tissues.

1. An acidic protein with properties similar to those of troponin C from rabbit skeletal muscle has been shown to be present in bovine and rabbit smooth muscles, chicken gizzard and rabbit liver, kidney and lung. 2. A simple new method involving the use of organic solvents is described for the purification of the troponin C-like proteins from various tissues. 3. The troponin C-like proteins can be distinguished from rabbit skeletal-muscle toponin C by their electrophoretic behaviour on polyacrylamide gels at pH 8.3 in the presence and absence of Ca2+. The troponin C-like proteins have been shown to form complexes with rabbit skeletal-muscle troponin I that migrate on electrophoresis in polyacrylamide gels. 4. Behaviour on electrophoresis, amino acid analysis and the patterns of CNBr digests on polyacrylamide gels indicate that the troponin C-like proteins from bovine uterus and aorta, rabbit uterus, and liver and chicken gizzard are very similar to, if not identical with, bovine brain modulator protein. 5. With bovine cardiac muscle the organic-solvent method yields a preparation consisting of roughly similar amounts of troponin C and troponin C-like protein. 6. By the isotope-dilution technique, troponin C-like protein has been shown to represent 0.42% of the total protein in rabbit uterus. 7. In homogenates of smooth muscle, rabbit lung, kidney and brain, the troponin C-like proteins form a complex with other protein (or proteins) that requires Ca2+ for its formation and that is not dissociated in 9M-urea.

Amino Acids↗
PubMed1978

Kinetics and regulation of the myofibrillar adenosine triphosphatase.

1. The steady-state kinetic behaviour of the ATPase (adenosine triphosphatase) of intact myofibrils was studied in the presence of both high and low concentrations of Ca2+ (0.25 mM and less than 10 nM respectively). 2. Kinetic data were collected over the initial linear phase of the assay, which lasts for 20--60s. To obtain consistent data we found it necessary to use either fresh myofibril preparations or preparations that had been stored in the presence of thiol compounds. 3. When assayed in the presence of 0.25 mM-Ca2+, the myofibrillar ATPase obeyed Michaelis-Menten kinetics over the range 0.03--5.0 mM-MgATP (Km 16 +/- 6 micrometer, V 0.4 +/- 0.1 mumol/min per mg). 4. At low Ca2+ concentrations (less than 10 nM) the myofibrillar ATPase displayed pronounced substrate inhibition, which was not observed at high Ca2+ concentrations. Thus increasing the MgATP concentration had the net effect of decreasing the ATPase activity at low Ca2+ relative to that at high Ca2+. This preferential effect of MgATP on the low-Ca2+ ATPase may be important in Ca2+ control. 5. The substrate inhibition that was observed at low Ca2+ was lost on storage or thiol modification of the myofibrils. 6. Under physiological conditions (2 mM-MgATP, I 0.15, pH 7.0), the ATPase of fresh and thiol-protected myofibrils displayed approx. 100-fold activation by Ca2+.

Adenosine Triphosphatases↗
PubMed1978

Characterization of a region of the primary sequence of troponin C involved in calcium ion-dependent interaction with troponin I.

1. The CNBr digest of troponin C from rabbit fast skeletal muscle was shown to possess many of the functional properties of the whole troponin C molecule. 2. A peptide corresponding to residues 83-134 was isolated, which forms a Ca(2+-dependent complex with troponin I and neutralizes the inhibition by troponin I of the Mg(2+-stimulated adenosine triphosphatase of desensitized actomyosin. 3. The peptide inhibits the phosphorylation of fast-skeletal-muscle, but not cardiac-muscle, troponin I, by 3' :5'-cyclic AMP-dependent protein kinase. In this property it was as effective as whole skeletal-muscle troponin C when compared on a molar basis. 4. Biological activity was also present in other fractions obtained from the CNBr digest. 5. By gel filtration and affinity chromatography of the whole CNBr digest of troponin C, two peptides, one of which was identified as representing residues 83-134, were shown to form Ca(2+-dependent complexes with troponin I. 6. The significance of these findings for the mechanism of interaction of troponin C and troponin I is discussed.

Adenosine Triphosphatases↗
PubMed1978

Troponin I from human skeletal and cardiac muscles.

1. Myofibrils from human skeletal muscle contained regulatory proteins exhibiting similar electrophoretic behaviour to those present in rabbit skeletal muscle. 2. All human skeletal muscles examined contained two forms of troponin I corresponding to the forms already characterized in fast and slow rabbit muscle. 3. The ratios of the amounts of the two forms of troponin I in different human skeletal muscles were not identical with the ratios for the type 1 to type 2 fibres published in the literature. The ratios could, however, be arranged in the same rank order. 4. Primate heart contained a single form of troponin I different in molecular weight and amino acid composition from the skeletal forms. 5. A monospecific antiserum to human cardiac troponin I was prepared in the sheep and shown not to react with the fast or slow skeletal-muscle forms of troponin I from human and other species. 6. The anti-(human cardiac-muscle troponin I) reacted with the cardiac troponin I from the human, baboon, rabbit and rhesus monkey. Positive reactions were also obtained with urea extracts of whole cardiac tissue.

Amino Acids↗