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Abstract
Striated cardiac and skeletal muscles play very different roles in the body, but they are similar at the molecular level. In particular, contraction, regardless of the type of muscle, is a precise and complex process involving the integral protein myofilaments and their associated regulatory components. The smallest functional unit of muscle contraction is the sarcomere. Within the sarcomere can be found a sophisticated ensemble of proteins associated with the thick filaments (myosin, myosin binding protein-C, titin, and obscurin) and thin myofilaments (actin, troponin, tropomyosin, nebulin, and nebulette). These parallel thick and thin filaments slide across one another, pulling the two ends of the sarcomere together to regulate contraction. More specifically, the regulation of both timing and force of contraction is accomplished through an intricate network of intra- and interfilament interactions belonging to each myofilament. This review introduces the sarcomere proteins involved in striated muscle contraction and places greater emphasis on the more recently identified and less well-characterized myofilaments: cardiac myosin binding protein-C, titin, nebulin, and obscurin. © 2017 American Physiological Society. Compr Physiol 7:675-692, 2017.
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Affiliation(s)
- Brian Leei Lin
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA
| | - Taejeong Song
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA.,Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Sakthivel Sadayappan
- Department of Cell and Molecular Physiology, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, USA.,Department of Internal Medicine, Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Sciences, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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Martinek K, Mozhaev VV. Immobilization of enzymes: an approach to fundamental studies in biochemistry. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 57:179-249. [PMID: 3898741 DOI: 10.1002/9780470123034.ch3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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3
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Green NS, Reisler E, Houk KN. Quantitative evaluation of the lengths of homobifunctional protein cross-linking reagents used as molecular rulers. Protein Sci 2001; 10:1293-304. [PMID: 11420431 PMCID: PMC2374107 DOI: 10.1110/ps.51201] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2000] [Revised: 03/26/2001] [Accepted: 03/26/2001] [Indexed: 01/16/2023]
Abstract
UNLABELLED Homobifunctional chemical cross-linking reagents are important tools for functional and structural characterization of proteins. Accurate measures of the lengths of these molecules currently are not available, despite their widespread use. Stochastic dynamics calculations now provide quantitative measures of the lengths, and length dispersions, of 32 widely used molecular rulers. Significant differences from published data have been found. SUPPLEMENTAL MATERIAL See www.proteinscience.org
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Affiliation(s)
- N S Green
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
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4
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Abstract
Troponin T (TnT) is present in striated muscle of vertebrates and invertebrates as a group of homologous proteins with molecular weights usually in the 31-36 kDa range. It occupies a unique role in the regulatory protein system in that it interacts with TnC and TnI of the troponin complex and the proteins of the myofibrillar thin filament, tropomyosin and actin. In the myofibril the molecule is about 18 nm long and for much its length interacts with tropomyosin. The ability of TnT to form a complex with tropomyosin is responsible for locating the troponin complex with a periodicity of 38.5 nm along the thin filament of the myofibril. In addition to it structural role, TnT has the important function of transforming the TnI-TnC complex into a system, the inhibitory activity of which, on the tropomyosin-actomyosin MgATPase of the myofibril, becomes sensitive to calcium ions. Different genes control the expression of TnT in fast skeletal, slow skeletal and cardiac muscles. In all muscles, and particularly in fast skeletal, alternative splicing of mRNA produces a series of isoforms in a developmentally regulated manner. In consequence TnT exists in many more isoforms than any of the other thin filament proteins, the TnT superfamily. Despite the general homology of TnT isoforms, this alternative splicing leads to variable regions close to the N- and C-termini. As the isoforms have slightly different effects on the calcium sensitivity of the actomyosin MgATPase, modulation of the contractile response to calcium can occur during development and in different muscle types. TnT has recently aroused clinical interest in its potential for detecting myocardial damage and the association of mutations in the cardiac isoform with hypertrophic cardiomyopathy.
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Affiliation(s)
- S V Perry
- Department of Physiology, Medical School, University of Birmingham, UK
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5
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De Felice C, Hayakawa K, Watanabe T, Tanaka T. High-performance gel-permeation chromatographic analysis of protein aggregation. Application to bovine carbonic anhydrase. J Chromatogr A 1993; 645:101-5. [PMID: 8408411 DOI: 10.1016/0021-9673(93)80623-g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Protein association in bovine carbonic anhydrase (bCA) was investigated by high-performance gel-permeation chromatography (HPGPC). It was shown that bCA undergoes a time-dependent aggregation after freezing and storing at -20 degrees C. The addition of 50% ethylene glycol or glycerol prevented the aggregation. The HPGPC data were confirmed by the use of cross-linking with subsequent sodium dodecyl sulphate-polyacrylamide gel electrophoretic analysis. The esterase activity of the aggregated bCA was comparable to that of the monomer, suggesting that the observed protein association does not affect the esterase catalytic centre of bCA. This study illustrates how HPGPC can be a convenient and reliable tool for monitoring storage-induced aggregation of proteins.
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Affiliation(s)
- C De Felice
- Endocrine Research Laboratory, National Children's Medical Research Centre, Tokyo, Japan
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Kay CM, McCubbin WD, Sykes BD. Biophysical studies on the calcium trigger of muscle contraction. Biopolymers 1987; 26 Suppl:S123-44. [PMID: 3580494 DOI: 10.1002/bip.360260013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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7
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Kareva VV, Dobrovol'sky AB, Baratova LA, Friedrich P, Gusev NB. Ca2+-induced structural change in the Ca2+/Mg2+ domain of troponin C detected by crosslinking. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 869:322-9. [PMID: 3947641 DOI: 10.1016/0167-4838(86)90072-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Rabbit muscle troponin C was selectively modified at Cys-98 by 1,3-difluoro-4,6-dinitrobenzene. The second function of the bifunctional reagent was triggered at alkaline pH in the presence and absence of Ca2+. The crosslinked troponin C was hydrolyzed by trypsin and the peptides containing a dinitrobenzene moiety were isolated. When troponin C was crosslinked in the presence of Ca2+, the single dinitrobenzene-containing peptide was Gly-89-Arg-100, in which Cys-98 was crosslinked with Lys-90. When crosslinking was performed in the absence of Ca2+, beside the above peptide two additional peptides containing dinitrobenzene were found. One of these peptides is made up of two fragments, Ser-91-Arg-100 and Asn-105-Arg-120, crosslinked between Cys-98 and Tyr-109. The second peptide, Ala-121-Lys-140, contains modified Lys-136, presumably crosslinked with His-135. The data indicate that the distances between the alpha-carbon of Cys-98 and those of Lys-90, Tyr-109, Lys-136 and probably the alpha-carbon distance His-125-Lys-136, do not exceed 14 A. Comparison with the X-ray structure of troponin C (Herzberg, O. and James, M.N.G. (1985) Nature 313, 653-659) indicates that some of the above distances increase on Ca2+-binding.
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Ohtsuki I, Maruyama K, Ebashi S. Regulatory and cytoskeletal proteins of vertebrate skeletal muscle. ADVANCES IN PROTEIN CHEMISTRY 1986; 38:1-67. [PMID: 3541537 DOI: 10.1016/s0065-3233(08)60525-2] [Citation(s) in RCA: 163] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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9
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Dobrovol'sky AB, Gusev NB, Friedrich P. Crosslinking of troponin complex with 1,3-difluoro-4,6-dinitrobenzene. Identification of the crosslink formed between troponin C and troponin I in the absence of Ca2+. BIOCHIMICA ET BIOPHYSICA ACTA 1984; 789:144-51. [PMID: 6477927 DOI: 10.1016/0167-4838(84)90198-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The single SH-group of rabbit skeletal muscle troponin C (Cys-98) was reacted with the bifunctional reagent, 1,3-difluoro-4,6-dinitrobenzene. This labelled troponin C was used to reconstitute the troponin complex by the addition of equimolar amounts of troponin T and troponin I. The second function of the bifunctional reagent was triggered in the complex by an increase of pH. A crosslink was formed between troponin C and troponin I both in the presence and absence of Ca2+, but the probability of crosslinking was decreased by Ca2+. Covalently linked troponin C-troponin I was isolated from the complex crosslinked without Ca2+, and cleaved by CNBr. The analysis of crosslinked peptides has revealed that in the presence of Mg2+ and absence of Ca2+ the crosslink in the troponin complex is formed between Cys-98 of troponin C and Cys-133 of troponin I.
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11
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Tarvers RC, Roberts HR, Lundblad RL. Self-association of bovine prothrombin fragment 1 in the presence of metal ions. Use of a covalent cross-linking reagent to study the reaction. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)43498-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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12
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Leavis PC, Gergely J. Thin filament proteins and thin filament-linked regulation of vertebrate muscle contraction. CRC CRITICAL REVIEWS IN BIOCHEMISTRY 1984; 16:235-305. [PMID: 6383715 DOI: 10.3109/10409238409108717] [Citation(s) in RCA: 346] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Recent developments in the field of myofibrillar proteins will be reviewed. Consideration will be given to the proteins that participate in the contractile process itself as well as to those involved in Ca-dependent regulation of striated (skeletal and cardiac) and smooth muscle. The relation of protein structure to function will be emphasized and the relation of various physiologically and histochemically defined fiber types to the proteins found in them will be discussed.
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13
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Moir AJ, Ordidge M, Grand RJ, Trayer IP, Perry SV. Studies of the interaction of troponin I with proteins of the I-filament and calmodulin. Biochem J 1983; 209:417-26. [PMID: 6847627 PMCID: PMC1154108 DOI: 10.1042/bj2090417] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
1. All lysine residues in native troponin I from rabbit fast-twitch skeletal muscle reacted with methyl acetimidate and ethyl acetimidate. 2. The reactivity of lysine-18 of troponin I to acetimidate was much diminished when the troponin I was complexed in the presence of Ca2+ with troponin C alone or in the whole troponin complex. 3. In the presence of EGTA, lysine-18 of troponin I in the troponin I-troponin C complex was more reactive to acetimidate than it was in the presence of Ca2+. 4. No masking of lysine residues could be detected when troponin I interacted with calmodulin or actin. 5. Sedimentation-equilibrium studies indicated that the complex of troponin I with calmodulin was more readily dissociated in the absence of Ca2+ than was its complex with troponin C under otherwise identical conditions. 6. These studies suggest that the nature of the involvement of the N-terminal region of troponin I is a major difference between its modes of interaction with calmodulin and with troponin C.
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14
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Photochemical cross-linking between rabbit skeletal troponin subunits. Troponin I-troponin T interactions. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)33814-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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15
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Hitchcock-De Gregori SE. Study of the structure of troponin-I by measuring the relative reactivities of lysines with acetic anhydride. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34387-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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16
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Formation of 5-carbomethoxyvaleramidine during hydrolysis of the protein cross-linking agent dimethyl adipimidate. ACTA ACUST UNITED AC 1982. [DOI: 10.1007/bf01025636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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17
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Proximity of sulfhydryl groups to the sites of interaction between components of the troponin complex from rabbit skeletal muscle. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34959-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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18
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McCubbin WD, Kay CM. Optical activity measurements for elucidating structure--function relationships in muscle protein systems. Methods Enzymol 1982; 85 Pt B:677-98. [PMID: 6214693 DOI: 10.1016/0076-6879(82)85056-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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19
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Grabarek Z, Drabikowski W, Leavis P, Rosenfeld S, Gergely J. Proteolytic fragments of troponin C. Interactions with the other troponin subunits and biological activity. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(18)43015-3] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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20
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Chong P, Hodges R. A new heterobifunctional cross-linking reagent for the study of biological interactions between proteins. II. Application to the troponin C-troponin I interaction. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69368-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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21
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Hitchcock SE, Zimmerman CJ, Smalley C. Study of the structure of troponin-T by measuring the relative reactivities of lysines with acetic anhydride. J Mol Biol 1981; 147:125-51. [PMID: 6790714 DOI: 10.1016/0022-2836(81)90082-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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22
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Hitchcock SE. Study of the structure of troponin-C by measuring the relative reactivities of lysines with acetic anhydride. J Mol Biol 1981; 147:153-73. [PMID: 6790715 DOI: 10.1016/0022-2836(81)90083-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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23
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Gusev NB, Friedrich P. Ca2+-induced conformational changes in the troponin complex detected by crosslinking. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 626:106-16. [PMID: 6779874 DOI: 10.1016/0005-2795(80)90202-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In an attempt to detect Ca2+-induced conformational changes by crosslinking, rabbit muscle troponin complex was reacted with the bifunctional reagents 1,3-difluoro-4,6-dinitrobenzene, 4,4'-difluoro-3,3'-dinitrodiphenylsulfone and dimethyl suberimidate under various conditions and the products were analyzed by dodecyl sulfate gel electrophoresis. In the absence of divalent cations, with the two aromatic reagents at a low reagent/protein ratio, the main cross-link products were troponin T-I and I-C. With dimethyl suberimidate the only major crosslink product was conjugate T-I. Ca2+, alone as well as in the presence of Mg2+, prevented the formation of I-C crosslinks with both aromatic reagents, but it did not affect crosslinking with dimethyl suberimidate. Ca2+ also decreased the number of NH2 groups of troponin that are highly reactive towards 2,4,6-trinitrobenzene sulfonate. Both effects of Ca2+ can be interpreted in terms of a conformational change in the troponin complex elicited by the binding of the specific divalent cation.
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Sutoh K, Matsuzaki F. Millisecond photo-cross-linking of protein components in vertebrate striated muscle thin filaments. Biochemistry 1980; 19:3878-82. [PMID: 6447509 DOI: 10.1021/bi00557a037] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Troponin I (TnI) was reacted with a photosensitive heterobifunctional reagent, methyl 4-azidobenzimidate (ABI), and then troponin was reconstituted with the ABI-modified TnI. Flash irradiation of the reconstituted troponin resulted in the formation of cross-links between TnI and other components of troponin, troponin C (TnC) and troponin T (TnT), suggesting that TnI is in contact with TnC and TnT when troponin is free in solution. No effect of calcium on the cross-linking could be detected. When the reconstituted troponin was complexed with F-actin-tropomyosin, flash irradiation of the reconstituted then filament yielded the cross-linked products of TnC-TnI, TnI-TnT, and TnI-actin in the presence ans absence of calcium, indicating that TnI is in contact with TnC, TnT, and actin in the thin filament complex irrespective of calcium concentration. No cross-linking could be detected between TnI and tropomyosin. Calcium was found to affect the cross-linking of TnC-TnI and TnI-actin; when TnC was saturated with calcium, the extent of the TnC-TnI cross-linking increased, while that of the TnI-actin cross-linking decreased. Calcium did not affect the TnI-TnT cross-linking.
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Reisler E, Liu J, Mercola M, Horwitz J. The interaction of Cibacron Blue F3GA with troponin and its subunits. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 623:243-56. [PMID: 6893162 DOI: 10.1016/0005-2795(80)90253-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Binding of troponin to Cibacron Blue F3GA-agarose column and its selective release from the gel in the presence of 0.5 M KCl provides the basis for a new purification method. The two-step procedure consists of isoelectric precipitation of tropomyosin and chromatography of the resultant crude troponin supernatant on Affi-Gel Blue column. Adsorption of troponin to the immobilized dye appears to occur through the troponin-T subunit. Troponin-I and troponin-C do not bind to the blue agarose column, whereas troponin-T binds to it very tightly. Binding of the dye to troponin-T prevents formation of troponin-T-troponin-C complex, but does not interfere with direct interaction of troponin-T with troponin-I. The activity of troponin in conferring calcium sensitivity on actomyosin ATPase is not affected by Cibacron Blue. Circular dichroism and difference absorption measurements of complexes of the blue dye with troponin and its subunits reveal the presence of a tight binding site on whole troponin and on troponin-T (KA greater than or equal to 10(6) M). The existence of weak binding sites for the dye on troponin and all of its subunits is deduced from difference absorption studies. Cibacron Blue appears to be a sensitive probe for subunit interactions in troponin.
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Siezen RJ, Bindels JG, Hoenders HJ. The quaternary structure of bovine alpha-crystallin. Chemical crosslinking with bifunctional imido esters. EUROPEAN JOURNAL OF BIOCHEMISTRY 1980; 107:243-9. [PMID: 7398636 DOI: 10.1111/j.1432-1033.1980.tb04644.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Reaction of calf alpha-crystallin, which consists of about 30 A and 10 B subunits, with various bisimido esters at pH 8.0-8.5 and room temperature leads to inter-subunit crosslinking. Little difference is observed in the efficiency of crosslinking by reagents of a homologous series with different lengths (from C6 to C12). At any stage of the reaction an exponential decrease is found in the amounts of crosslinked dimer, trimer, tetramer etc., with no preference for the formation of any particular oligomer, suggesting that all subunits on the surface of the spherical alpha-crystallin molecule are in quasi-equivalent positions. Molecular weight analysis by docdecylsulfate gel electrophoresis and reversible crosslinking show that both A and B subunits occur in an apparently constant ratio in the crosslinked oligomers, from which we infer that both types of subunits are randomly arranged on the surface of the alpha-crystallin molecule. Not all of the subunits can form inter-chain crosslinks, as a limiting value of about 60% of the subunits is found in oligomeric form. A simple explanation could be a core of subunits which is inaccessible to certain chemical reagents, although other alternatives are also discussed.
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Sutoh K. Direct evidence for the calcium-induced change in the quaternary structure of troponin in situ. Millisecond cross-linking of troponin components by a photosensitive heterobifunctional reagent. Biochemistry 1980; 19:1977-83. [PMID: 7378388 DOI: 10.1021/bi00550a038] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Flash irradiation of the reconstituted troponin of thin filament complex in which one of their components, troponin C, was modified with a heterobifunctional photosensitive reagent before reconstitution of the troponin complex resulted in the formation of cross-links between troponin C and other components in contact with it. Quantitative analysis of the cross-linked products by gel electrophoresis has revealed interesting features of the quaternary structure of troponin. When the reconstituted troponin was photo-cross-linked with a xenon flash, an appreciable amount of cross-linking was detected between troponin C and troponin I and also between troponin C and troponin T. No effect of calcium on the cross-linking could be detected. This arrangement of components was found to change when troponin was complexed with F-actin-tropomyosin. The arrangement of troponin components in the thin filament complex was sensitive to calcium and magnesium; maximum cross-linking of troponin C and troponin I was observed when the thin filament was cross-linked in the presence of calcium and magnesium, while an appreciable decrease in the extent of the cross-linking was detected when calcium alone or calcium and magnesium were removed from the cross-linking medium. The cross-linking of troponin C and troponin T remained marginal irrespective of the concentration of calcium and magnesium.
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28
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Siezen RJ. Crosslinking of alpha-crystallin with bisimidoesters. Evidence for polyamidine formation at pH8 from an increase in positive charges on the polypeptide chains. FEBS Lett 1979; 100:75-80. [PMID: 35368 DOI: 10.1016/0014-5793(79)81134-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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29
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De Pont JJ. Reversible inactivation of (Na+ + K+)-ATPase by use of a cleavable bifunctional reagent. BIOCHIMICA ET BIOPHYSICA ACTA 1979; 567:247-56. [PMID: 36918 DOI: 10.1016/0005-2744(79)90191-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
1. Purified (Na+ + K+)-ATPase, prepared from rabbit kidney outer medulla, is incubated with the bifunctional NH2-directed reagent dimethyl 3,3'-dithiobis-propionimidate. This results in a cross-link between the subunits of the enzyme and a simultaneous reduction of the (Na+ + K+)-ATPase and K+-stimulated p-nitrophenylphosphatase activities. 2. The most abundant cross-link product is a dimer of the two different subunits of the enzyme. 3. Reduction of the disulfide cross-link by dithioerythritol results in partial recovery of the original subunit structure of the enzyme and of the (Na+ + K+)-ATPase and K+-stimulated p-nitrophenylphosphatase activities. 4. These results suggest that a free mobility of the subunits of the (Na+ + K+)-ATPase system relative to each other is essential for proper functioning of both enzyme activities.
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30
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Horwitz J, Bullard B, Mercola D. Interaction of troponin subunits. The interaction between the inhibitory and tropomyosin-binding subunits. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(17)37924-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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31
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Jue R, Lambert JM, Pierce LR, Traut RR. Addition of sulfhydryl groups to Escherichia coli ribosomes by protein modification with 2-iminothiolane (methyl 4-mercaptobutyrimidate). Biochemistry 1978; 17:5399-406. [PMID: 365229 DOI: 10.1021/bi00618a013] [Citation(s) in RCA: 160] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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32
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Nidamental gland precursor of the egg capsule protein of the gastropod mollusc Busycon carica. ACTA ACUST UNITED AC 1978. [DOI: 10.1016/0305-0491(78)90193-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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33
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Pearlstone JR, Carpenter MR, Smillie LB. Primary structure of rabbit skeletal muscle troponin-T. Purification of cyanogen bromide fragments and the amino acid sequence of fragment CB2. J Biol Chem 1977. [DOI: 10.1016/s0021-9258(19)75193-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Pearlstone JR, Johnson P, Carpenter MR, Smillie LB. Primary structure of rabbit skeletal muscle troponin-T. Sequence determination of the NH2-terminal fragment CB3 and the complete sequence of troponin-T. J Biol Chem 1977. [DOI: 10.1016/s0021-9258(19)75195-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Lambert JM, Perham RN. Folding domains and intramolecular ionic interactions of lysine residues in glyceraldehyde 3-phosphate dehydrogenase. Biochem J 1977; 161:49-62. [PMID: 851424 PMCID: PMC1164473 DOI: 10.1042/bj1610049] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
1. Treatment with methyl acetimidate was used to probe the topography of several tetrameric glyceraldehyde 3-phosphate dehydrogenases, in particular the holoenzymes from rabbit muscle and Bacillus stearothermophilus. During the course of the reaction with the rabbit muscle enzyme, the number of amino groups fell rapidly from the starting value of 27 per subunit to a value of approx. five per subunit. This number could be lowered further to values between one and two per subunit by a second treatment with methyl acetimidate. The enzyme remained tetrameric throughout and retained 50% of its initial catalytic activity at the end of the experiment. 2. Use of methyl [1-14C]acetimidate and small-scale methods of protein chemistry showed that only one amino group per subunit, that of lysine-306, was completely unavailable for reaction with imido ester in the native enzyme. This results is consistent with the structure of the highly homologous glyceraldehyde 3-phosphate dehydrogenase of lobster muscle deduced from X-ray-crystallographic analysis, since lysine-306 can be seen to form an intrachain ion-pair with aspartic acid-241 in the hydrophobic environment of a subunit-subunit interface. 3. Several other amino groups in the rabbit muscle enzyme that reacted only slowly with the reagent were also identified chemically. These were found to be located entirely in the C-terminal half of the polypeptides chain, which comprises a folding domain associated with catalytic activity and subunit contact in the three-dimensional structure. Slow reaction of these 'surface' amino groups with methyl acetimidate is attributed to intramolecular ionic interactions of the amino groups with neighbouring side-chain carboxyl groups, a conclusion that is compatible with the reported three-dimensional structure and with the dependence of the reaction of ionic stength. 4. Very similar results were obtained with the enzymes from B. stearothermophilus and from ox muscle and ox liver, supporting the view that the ion-pair involving lysine-306 and aspartic acid-241 will be a common structural feature in glyceraldehyde-3-phosphate dehydrogenases. The B. stearothermophilus enzyme was fully active after modification. 5. No differences could be detected between the enzymes from ox muscle and ox liver, in accord with other evidence that points to the identify of these enzymes. 6. The pattern of slowly reacting amino groups in the enzyme from B. stearothermophilus, although similar to that of the mammalian enzymes, indicated one or two additional intramolecular ionic interactions of lysine residues that might contribute to the thermal stability of this enzyme.
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Swaney JB, O'Brien KJ. Cross-linking studies on the state of association of apo A-I and apo A-II from human HDL. Biochem Biophys Res Commun 1976; 71:636-43. [PMID: 183777 DOI: 10.1016/0006-291x(76)90835-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Pearlstone JR, Carpenter MR, Johnson P, Smillie LB. Amino-acid sequence of tropomyosin-binding component of rabbit skeletal muscle troponin. Proc Natl Acad Sci U S A 1976; 73:1902-6. [PMID: 1064862 PMCID: PMC430415 DOI: 10.1073/pnas.73.6.1902] [Citation(s) in RCA: 91] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The complete amino-acid sequence of rabbit skeletal troponin-T is reported. The protein consists of a single polypeptide chain of 259 amino acids; it has an acetylated amino terminus and a molecular weight of 30,503. The sequence was determined by manual and/or automated Edman degradation techniques on the six fragments obtained after cleavage with cyanogen bromide. The larger fragments were further digested with trypsin, chymotrypsin, alpha-lytic protease, thermolysin, or pepsin to obtain smaller fragments suitable for manual sequencing. About 50% of the residues are charged at neutral pH with highly acidic amino-terminal (residues 1-39) and highly basic carboxyl-terminal regions (residues 221-259). Predictions of secondary structure indicate 37% helical content with two long sections (residues 80-102 and 122-146) in that portion of the molecule implicated in binding to tropomyocin. Two of the three phosphorylated sites in the molecule are located at serine-1 and serine-149 or -150. The sequence about the latter site resembles somewhat the phosphorylase kinase phosphorylation sites in phosphorylase alpha and troponin-I.
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