scholarly journals Biological activities of bovine cardiac-muscle troponin C C-terminal peptide (residues 84-161)

1982 ◽  
Vol 207 (2) ◽  
pp. 185-192 ◽  
Author(s):  
N V Barskaya ◽  
N B Gusev
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Cardiac Muscle ◽  
Sodium Dodecyl Sulphate ◽  
Binding Sites ◽  
Binding Constant ◽  
Troponin I ◽  
Biological Activities ◽  
Sodium Dodecyl ◽  
Troponin C

1. Bovine cardiac-muscle troponin C was digested at cysteine residues 35 and 84, and the C-terminal peptide (residues 84-161) was isolated. 2. The C-terminal peptide contains two Ca2+-binding sites. These sites bind Ca2+ with a binding constant of 2.0×10(8) M-1. In the presence of 2 mM-Mg2+ the binding constant for Ca2+ is decreased to 3.70×10(7) M-1. The corresponding constants for native troponin C are 5.90×10(7) M-1. and 2.90×10(7) M-1 respectively. 3. Electrophoretic mobility of the C-terminal peptide is increased in the presence of 0.1 mM-CaCl2 as compared with the mobility in the presence of 2mM-EDTA. The same phenomenon was observed when electrophoresis was performed in the presence of 6 M-urea or 0.1% sodium dodecyl sulphate. 4. When saturated with Ca2+, the C-terminal peptide forms complexes with bovine cardiac-muscle troponin I both in the absence and in the presence of 6 M-urea. This complex is dissociated on removal of Ca2+. 5. The data suggest that the C-terminal peptide of troponin C contains two Ca2+/Mg2+-binding sites and interacts with troponin I. Thus, despite the 30% difference in amino acid composition, the properties of bovine cardiac-muscle troponin C C-terminal peptide are similar to those of rabbit skeletal-muscle troponin C C-terminal peptide.

The binding sites of rabbit skeletal troponin-I on troponin-T

1980 ◽  
Vol 58 (8) ◽  
pp. 649-654 ◽  
Author(s):  
Joyce R. Pearlstone ◽  
Lawrence B. Smillie
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Binding Site ◽  
Binding Sites ◽  
Troponin I ◽  
Troponin T ◽  
Gel Filtration ◽  
Troponin C ◽  
Separate Site

Various fragments derived from rabbit skeletal muscle troponin-T (Tn-T) by chemical and (or) proteolytic cleavage were mixed with whole troponin-I (Tn-I) and applied to a Sephadex G-75 gel filtration column in order to determine the binding site of Tn-I on Tn-T. This site of interaction was found to span two distinct regions of Tn-T. The first site involves the highly acidic NH2-terminal fragment CB3 (residues 1–70 of Tn-T). A second separate site is located in the region of residues 152–209 of Tn-T. The present study, in conjunction with our earlier work on tropomyosin – Tn-T binding and Tn-T – troponin-C binding, depicts Tn-T as being a functionally efficient molecule composed of several distinct domains of specialized amino acid sequence, each of which carries out a role in the binding of a different protein.

scholarly journals A phosphorylated light-chain component of myosin from skeletal muscle

1973 ◽  
Vol 135 (1) ◽  
pp. 151-164 ◽  
Author(s):  
W. T. Perrie ◽  
L. B. Smillie ◽  
S. V. Perry
Keyword(s):  
Skeletal Muscle ◽  
Molecular Weight ◽  
Amino Acid ◽  
Light Chain ◽  
Sodium Dodecyl Sulphate ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Low Molecular Weight ◽  
Obvious Similarity

1. The low-molecular-weight components of myosin from rabbit skeletal muscle migrated as four bands on polyacrylamide-gel electrophoresis in 8m-urea but only as three in systems containing sodium dodecyl sulphate. The two bands of intermediate mobility in 8m-urea (Ml2 and Ml3) had identical mobilities in sodium dodecyl sulphate. 2. The isolation of pure samples of all four low-molecular-weight components by DEAE-Sephadex chromatography is described. 3. The amino acid compositions of components Ml2 and Ml3 were identical. Further analyses showed the presence of 1 mol of phosphate/18500g of component Ml2 and less than 10% of this amount in component Ml3. Neither light component contained ribose. 4. Alkaline phosphatase from Escherichia coli converted component Ml2 into Ml3. Incubation with crude preparations of phosphorylase b kinase or protein kinase in the presence of ATP converted component Ml3 into Ml2. 5. Phosphorylation of component Ml3 with the kinases isolated from skeletal muscle and [γ-32P]ATP gave incorporation of 32P only into component Ml2 whether whole myosin or separated low-molecular-weight components were used. 6. High-voltage electrophoresis at pH6.5 and pH1.8 of a chymotryptic digest of 32P-labelled component Ml2 yielded one major radioactive peptide containing serine phosphate. 7. The amino acid sequence of this peptide was shown to be: Arg-Ala-Ala-Ala-Glu-Gly-Gly-(Ser,Ser(P))-Asn-Val-Phe. This sequence shows no obvious similarity to the site phosphorylated in the conversion of phosphorylase b into phosphorylase a by phosphorylase b kinase. 8. Evidence suggests that in vivo all the 18500-molecular-weight light chain is in the phosphorylated form. The extent of dephosphorylation that occurred during myosin extraction depended on the conditions employed.

scholarly journals Affinity-chromatographic isolation and some properties of troponin C from different muscle types

1977 ◽  
Vol 161 (3) ◽  
pp. 465-471 ◽  
Author(s):  
J F Head ◽  
R A Weeks ◽  
S V Perry
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Troponin I ◽  
Smooth Muscles ◽  
Troponin C ◽  
Electrophoretic Mobilities ◽  
Muscle Types ◽  
Chromatographic Isolation

1. The formation of a complex between troponin I and troponin C that is stable in 6M-urea and dependent on Ca2+ was demonstrated in extracts of vertebrate striated and smooth muscles. 2. A method using troponin I coupled to Sepharose is described for the rapid isolation of troponin C from striated and smooth muscles of vertebrates. 3. Troponin C of rabbit cardiac muscle differs significantly in amino acid composition from troponin C of skeletal muscle. The primary structures of troponin C of red and white skeletal muscle are very similar. 4. The troponin C-like protein isolated from rabbit uterus muscle has a slightly different amino acid composition, but possess many similar properties to the forms of troponin C isolated from other muscle types. 5. The electrophoretic mobilities of the I-troponin C complexes formed from components isolated from different muscle types are determined by the troponin I component.

scholarly journals Proteolytic fragments of troponin C. Localization of high and low affinity Ca2+ binding sites and interactions with troponin I and troponin T

1978 ◽  
Vol 253 (15) ◽  
pp. 5452-5459
Author(s):  
P.C. Leavis ◽  
S.S. Rosenfeld ◽  
J. Gergely ◽  
Z. Grabarek ◽  
W. Drabikowski
Keyword(s):  
Binding Sites ◽  
Troponin I ◽  
Troponin T ◽  
Troponin C

scholarly journals The phosphorylation of troponin I from cardiac muscle

1975 ◽  
Vol 149 (3) ◽  
pp. 525-533 ◽  
Author(s):  
H A Cole ◽  
S V Perry
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Cardiac Muscle ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Cardiac Troponin I ◽  
Phosphorylase Kinase ◽  
Dependent Protein Kinase ◽  
Dependent Protein

1. Troponin I isolated from fresh cardiac muscle by affinity chromatography contains about 1.9 mol of covalently bound phosphate/mol. Similar preparations of white-skeletal-muscle troponin I contain about 0.5 mol of phosphate/mol. 2. A 3':5'-cyclic AMP-dependent protein kinase and a protein phosphatase are associated with troponin isolated from cardiac muscle. 3. Bovine cardiac 3':5'-cyclic AMP-dependent protein kinase catalyses the phosphorylation of cardiac troponin I 30 times faster than white-skeletal-muscle troponin I. 4. Troponin I is the only component of cardiac troponin phosphorylated at a significant rate by the endogenous or a bovine cardiac 3':5'-cyclic AMP-dependent protein kinase. 5. Phosphorylase kinase catalyses the phosphorylation of cardiac troponin I at similar or slightly faster rates than white-skeletal-muscle troponin I. 6. Troponin C inhibits the phosphorylation of cardiac and skeletal troponin I catalysed by phosphorylase kinase and the phosphorylation of white skeletal troponin I catalysed by 3':5'-cyclic AMP-dependent protein kinase; the phosphorylation of cardiac troponin I catalysed by the latter enzyme is not inhibited.

scholarly journals The molybdenum–iron protein of Klebsiella pneumoniae nitrogenase. Evidence for non-identical subunits from peptide ‘mapping’

1976 ◽  
Vol 155 (2) ◽  
pp. 383-389 ◽  
Author(s):  
C Kennedy ◽  
R R. Eady ◽  
E Kondorosi ◽  
D K Rekosh
Keyword(s):  
Amino Acid ◽  
Klebsiella Pneumoniae ◽  
Sodium Dodecyl Sulphate ◽  
Azotobacter Vinelandii ◽  
Peptide Mapping ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Amino Acid Content ◽  
Rhizobium Japonicum ◽  
Fe Protein

The molybdenum- and iron-containing protein components of nitrogenase purified from Klebsiella pneumoniae, Azotobacter vinelandii, Azotobacter chroococcum and Rhizobium japonicum bacteroids all gave either one or two protein-staining bands after sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, depending on the commercial brand of sodium dodecyl sulphate used. The single band obtained with K. pneumoniae Mo-Fe protein when some commercial brands of sodium dodecyl sulphate were used in the preparation of the electrode buffer was resolved into two bands by the addition of 0.01% (v/v) dodecanol to the buffer. Protein extracted from the two bands obtained after electrophoresis of K. pneumoniae Mo-Fe protein gave unique and distinct peptide ‘maps’ after tryptic digestion. Undissociated Mo-Fe protein contained both sets of tryptic peptides. These data are consistent with Mo-Fe protein from K. pneumoniae being composed of non-identical subunits. Amino acid analyses of the subunit proteins revealed some clear differences in amino acid content, but the two subunits showed close compositional relatedness, with a different index [Metzer, H., Shapiro, M.B., Mosiman, J.E. & Vinton, J.G. (1968) Nature (London) 219, 1166-1168] of 4.7.

scholarly journals Structural properties of homogeneous protein disulphide-isomerase from bovine liver purified by a rapid high-yielding procedure

1983 ◽  
Vol 213 (1) ◽  
pp. 225-234 ◽  
Author(s):  
N Lambert ◽  
R B Freedman
Keyword(s):  
Amino Acid ◽  
Sodium Dodecyl Sulphate ◽  
Gel Electrophoresis ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Sedimentation Coefficient ◽  
Bovine Liver ◽  
Polyacrylamide Gel ◽  
Protein Disulphide Isomerase

Protein disulphide-isomerase from bovine liver was purified to homogeneity as judged by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, two-dimensional electrophoresis and N-terminal amino acid analysis. The preparative procedure, a modification of that of Carmichael, Morin & Dixon [(1977) J. Biol. Chem. 252, 7163-7167], is much faster and higher-yielding than previous procedures, and the final purified material is of higher specific activity. The enzyme has Mr 57 000 as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, both in the presence and in the absence of thiol compounds. Gel-filtration studies on Sephadex G-200 indicate an Mr of 107 000, suggesting that the native enzyme is a homodimer with no interchain disulphide bonds. Ultracentrifugation studies give a sedimentation coefficient of 3.5S, implying that the enzyme sediments as the monomer. The isoelectric point, in the presence of 8 M-urea, is 4.2, and some microheterogeneity is detectable. The amino acid composition is comparable with previous analyses of this enzyme from bovine liver and of other preparations of thiol:protein disulphide oxidoreductases whose relation to protein disulphide-isomerase has been controversial. The enzyme contains a very high proportion of Glx + Asx residues (27%). The N-terminal residue is His. The pure enzyme has a very small carbohydrate content, determined as 0.5-1.0% by the phenol/H2SO4 assay. Unless specific steps are taken to remove it, the purified enzyme contains a small amount (5 mol/mol of enzyme) of Triton X-100 carried through the purification.

scholarly journals Transcription factor GATA-4 regulates cardiac muscle-specific expression of the alpha-myosin heavy-chain gene.

1994 ◽  
Vol 14 (7) ◽  
pp. 4947-4957 ◽  
Author(s):  
J D Molkentin ◽  
D V Kalvakolanu ◽  
B E Markham
Keyword(s):  
Skeletal Muscle ◽  
Transcription Factor ◽  
Retinoic Acid ◽  
Cardiac Muscle ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Binding Sites ◽  
Ectopic Expression ◽  
Specific Expression ◽  
Cardiac Phenotype

The alpha-myosin heavy-chain (alpha-MHC) gene is the major structural protein in the adult rodent myocardium. Its expression is restricted to the heart by a complex interplay of trans-acting factors and their cis-acting sites. However, to date, the factors that have been shown to regulate expression of this gene have also been found in skeletal muscle cells. Recently, transcription factor GATA-4, which has a tissue distribution limited to the heart and endodermally derived tissues, was identified. We recently found two putative GATA-binding sites within the proximal enhancer of the alpha-MHC gene, suggesting that GATA-4 might regulate its expression. In this study, we establish that GATA-4 interacts with the alpha-MHC GATA sites to stimulate cardiac muscle-specific expression. Mutation of the GATA-4-binding sites either individually or together decreased activity by 50 and 88% in the adult myocardium, respectively. GATA-4-dependent enhancement of activity from a heterologous promoter was mediated through the alpha-MHC GATA sites. Coinjection of an alpha-MHC promoter construct with a GATA-4 expression vector permitted ectopic expression in skeletal muscle but not in fibroblasts. Thus, the lack of alpha-MHC expression in skeletal muscle correlates with a lack of GATA-4. GATA-4 DNA binding activity was significantly up-regulated in triiodothyronine- or retinoic acid-treated cardiomyocytes. Putative GATA-4-binding sites are also found in the regulatory regions of other cardiac muscle-expressed structural genes. This indicates a mechanism whereby triiodothyronine and retinoic acid can exert coordinate control of the cardiac phenotype through a trans-acting regulatory factor.

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