PMID: 3745212Sep 25, 1986Paper

Native chicken gizzard tropomyosin is predominantly a beta gamma-heterodimer.

The Journal of Biological Chemistry
C SandersL B Smillie

Abstract

Unmodified chicken gizzard tropomyosin (TM) has been fractionated into its two major isoforms beta and gamma, by chromatofocussing in the presence of 9 M urea and dithiothrieitol. Treatment of the native protein with several bifunctional N-hydroxysuccinimide esters gave the beta gamma-heterodimer as the major cross-linked product. A comparison of the thermal transition profiles of the two homodimers and of the native unfractionated TM also indicated the predominance of the beta gamma-heterodimer in the native protein. This conclusion is consistent with the absence of excimer fluorescence in pyrene-labeled gizzard TM and the relative resistance of the molecule to intramolecular disulfide formation (Lehrer, S.S., Betteridge, D.R., Graceffa, P., Wong, S., and Seidel, J. C. (1984) Biochemistry 23, 1591-1595) since the single cysteines on each of the two isoforms are widely separated. We conclude that further experimental evidence is required to assess the possibility that the gizzard TM is more rigid in its conformation than are those of the skeletal and cardiac proteins.

Related Concepts

Related Feeds

ASBMB Publications

The American Society for Biochemistry and Molecular Biology (ASBMB) includes the Journal of Biological Chemistry, Molecular & Cellular Proteomics, and the Journal of Lipid Research. Discover the latest research from ASBMB here.