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Cross-linking of residue 57 in the regulatory domain of a mutant rabbit skeletal muscle troponin C to the inhibitory region of troponin I
- Source :
- Scopus-Elsevier
- Publication Year :
- 1991
- Publisher :
- Elsevier BV, 1991.
-
Abstract
- Interactions between troponin C (TnC) and troponin I (TnI) play an important role in the Ca(2+)-dependent regulation of vertebrate striated muscle contraction. In the present study, we investigated the sites of interaction between the N-terminal regulatory domain of TnC and the inhibitory region (residues 96-116) of TnI, using a mutant rabbit skeletal TnC (designated as TnC57) that contains a single Cys at residue 57 in the C-helix. TnC57 was modified with the photoreactive cross-linker 4-maleimidobenzophenone (BP-Mal), and, after formation of a binary complex with TnI, cross-linking between the proteins was induced by photolysis. The resulting product was cleaved with CNBr and several proteases, and peptides containing cross-links were purified and subjected to amino acid sequencing. The results show that Cys-57 of TnC57 is cross-linked to the segment of TnI spanning residues 113-121. Previously, we showed that Cys-98 of TnC can be cross-linked via BP-Mal to TnI residues 103-110 (Leszyk, J., Collins, J.H., Leavis, P.C., and Tao, T. (1987) Biochemistry 26, 7042-7047). Taken together, these results demonstrate that both the C- and the N-terminal domains of TnC interact with the inhibitory region of TnI and are consistent with the hypothesis that, in a complex with TnI, TnC adopts a more compact conformation than in the crystal structure.
- Subjects :
- chemistry.chemical_classification
Skeletal muscle
Cell Biology
Plasma protein binding
Striated muscle contraction
Biology
musculoskeletal system
Biochemistry
Amino acid
Troponin C
medicine.anatomical_structure
Protein structure
chemistry
Troponin I
cardiovascular system
medicine
Molecular Biology
Peptide sequence
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 266
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....82abdcd6849eac783b51e0b8041ff9df