Functional homodimers and heterodimers of recombinant smooth muscle tropomyosin

Coulton, Arthur T. and Lehrer, Sherwin S. and Geeves, Michael A. (2006) Functional homodimers and heterodimers of recombinant smooth muscle tropomyosin. Biochemistry, 45 (42). pp. 12853-8. ISSN 0006-2960. (The full text of this publication is not available from this repository)

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Official URL
http://dx.doi.org/10.1021/bi0613224

Abstract

Skeletal and smooth muscle tropomyosin (Tm) require acetylation of their N-termini to bind strongly to actin. Tm containing an N-terminal alanine-serine (AS) extension to mimic acetylation has been widely used to increase binding. The current study investigates the ability of an N-terminal AS extension to mimic native acetylation for both alpha alpha and beta beta smooth Tm homodimers. We show that (1) AS alpha-Tm binds actin 100-fold tighter than alpha-Tm and 2-fold tighter than native smooth alphabeta-Tm, (2) beta-Tm requires an AS extension to bind actin, and (3) AS beta-Tm binds actin 10-fold weaker than AS alpha-Tm. Tm is present in smooth muscle tissues as >95% heterodimer; therefore, we studied the binding of recombinant alphabeta heterodimers with different AS extensions. This study shows that recombinant Tm requires an AS extension on both alpha and beta chains to bind like native Tm and that the alpha chain contributes more to actin binding than the beta chain. Once assembled onto an actin filament, all smooth muscle Tm's regulate S1 binding to actin Tm in the same way, irrespective of the presence of an AS extension.

Item Type: Article
Additional information: 0006-2960 (Print) Journal Article Research Support, N.I.H., Extramural
Uncontrolled keywords: Actins/metabolism Animals Base Sequence Chickens DNA Primers Dimerization Gizzard Kinetics Molecular Sequence Data Muscle, Smooth/*metabolism Polymerase Chain Reaction Recombinant Proteins/chemistry/metabolism Tropomyosin/*chemistry/*metabolism
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences
Depositing User: Michael Geeves
Date Deposited: 16 Mar 2009 16:21
Last Modified: 20 May 2014 15:51
Resource URI: http://kar.kent.ac.uk/id/eprint/13210 (The current URI for this page, for reference purposes)
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