The long-term objective of this project is to elucidate the mechanisms for 1) transduction of energy during contraction of skeletal muscle, 2) the regulation of skeletal muscle contraction by calcium ions. Since these two processes are fundamental to the functioning of normal muscle tissue, this work may provide insight into the nature of pathological muscle conditions. This objective will be achieved by determining the spatial relationships among the four major contractile proteins: myosin, actin, tropomyosin and troponin. Furthermore, how these spatial relationships change with the functional state of muscle (relaxed, activated, or in rigor) will be examined. Information so derived will be used to reconstruct the molecular events that occur during muscle contraction and its regulation. Principally, two techniques will be used to determine spatial relationships: excitation energy transfer, and photochemical crosslinking. The distances between sites in tropomyosin and in the three subunits of troponin will be determined by excitation energy transfer measurements. Simultaneously, amino acid residues at the interfaces between the proteins will be identified using photocrosslinking and peptide analysis techniques. Information derived from these studies will be used to construct a three-dimensional model for the troponin.tropomyosin complex. In a similar fashion, distances between sites in tropomyosin, actin and myosin will be determined, and the interaction interfaces between these proteins identified. This will yield information on the location of tropomyosin in the myosin.actin.tropomyosin complex, and the contact region between myosin and actin.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37AR021673-23
Application #
6171413
Study Section
Special Emphasis Panel (NSS)
Program Officer
Lymn, Richard W
Project Start
1979-08-01
Project End
2002-03-31
Budget Start
2000-04-01
Budget End
2002-03-31
Support Year
23
Fiscal Year
2000
Total Cost
$385,853
Indirect Cost
Name
Boston Biomedical Research Institute
Department
Type
DUNS #
058893371
City
Watertown
State
MA
Country
United States
Zip Code
02472
Mudalige, Wasana A K A; Tao, Terence C; Lehrer, Sherwin S (2009) Ca2+-dependent photocrosslinking of tropomyosin residue 146 to residues 157-163 in the C-terminal domain of troponin I in reconstituted skeletal muscle thin filaments. J Mol Biol 389:575-83
Luo, Yin; Leszyk, John; Li, Bing et al. (2002) Troponin-I interacts with the Met47 region of skeletal muscle actin. Implications for the mechanism of thin filament regulation by calcium. J Mol Biol 316:429-34
Luo, Yin; Li, Bing; Yang, Guang et al. (2002) Cross-linking between the regulatory regions of troponin-I and troponin-C abolishes the inhibitory function of troponin. Biochemistry 41:12891-8
Li, Z; Gergely, J; Tao, T (2001) Proximity relationships between residue 117 of rabbit skeletal troponin-I and residues in troponin-C and actin. Biophys J 81:321-33
Luo, Y; Leszyk, J; Li, B et al. (2000) Proximity relationships between residue 6 of troponin I and residues in troponin C: further evidence for extended conformation of troponin C in the troponin complex. Biochemistry 39:15306-15
Luo, Y; Wu, J L; Li, B et al. (2000) Photocrosslinking of benzophenone-labeled single cysteine troponin I mutants to other thin filament proteins. J Mol Biol 296:899-910
Moses, M A; Wiederschain, D; Wu, I et al. (1999) Troponin I is present in human cartilage and inhibits angiogenesis. Proc Natl Acad Sci U S A 96:2645-50
Tao, T; Gong, B J; Grabarek, Z et al. (1999) Conformational changes induced in troponin I by interaction with troponin T and actin/tropomyosin. Biochim Biophys Acta 1450:423-33
Mabuchi, K; Gong, B J; Langsetmo, K et al. (1999) Isoforms of the small non-catalytic subunit of smooth muscle myosin light chain phosphatase. Biochim Biophys Acta 1434:296-303
Luo, Y; Leszyk, J; Qian, Y et al. (1999) Residues 48 and 82 at the N-terminal hydrophobic pocket of rabbit skeletal muscle troponin-C photo-cross-link to Met121 of troponin-I. Biochemistry 38:6678-88

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