Publication Date:
1989-11-17
Description:
Rana esculenta tropomyosin assembles in vivo into a coiled-coil alpha helix from two different subunits, alpha and beta, which are present in about equal concentrations. Although the native composition is alpha beta, a mixture of equal amounts of alpha alpha and beta beta is produced by refolding dissociated alpha and beta at low temperature in vitro. Refolding kinetics showed that alpha alpha formed first and was relatively stable with regard to chain exchange below approximately 20 degrees C. Equilibration of the homodimer mixture at 30 degrees and 34 degrees C for long times, however, resulted in the formation of the native alpha beta molecule by chain exchange. Biosynthesis of alpha beta from separate alpha and beta genes is, therefore, favored thermodynamically over the formation of homodimers, and biological factors need not be invoked to explain the preferred native alpha beta composition.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lehrer, S S -- Qian, Y D -- Hvidt, S -- HL22461/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1989 Nov 17;246(4932):926-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Muscle Research, Boston Biomedical Research Institute, MA 02114.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2814515" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Kinetics
;
Macromolecular Substances
;
Muscle, Smooth/metabolism
;
Muscles/metabolism
;
Myocardium/metabolism
;
Protein Conformation
;
Protein Denaturation
;
Protein Processing, Post-Translational
;
Rana esculenta
;
Thermodynamics
;
Tropomyosin/genetics/*metabolism
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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