HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Fisher, M. T. Search for Related Content PubMed PubMed Citation Articles by Fisher, M. T. Social Bookmarking                      What's this?

J. Biol. Chem., Vol. 268, Issue 19, 13777-13779, Jul, 1993

On the assembly of dodecameric glutamine synthetase from stable chaperonin complexes

MT Fisher
Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66160-7421.

For many in vitro protein-folding reactions, the fraction of correctly folded product declines as the initial protein concentration increases due primarily to misfolding and aggregation reactions. Under optimal conditions and in the presence of ATP, chaperonins (groEL and groES) enhanced the renaturation of dodecameric glutamine synthetase (GS) with yields of active enzyme between 75 and 85% of the original activity (Fisher, M.T. (1992) Biochemistry 31, 3955-3963). In spite of this enhancement, a concentration-dependent decline in recoverable activity was observed when increasing concentrations of unfolded GS were rapidly mixed with renaturation buffer containing a 2-fold molar excess (GS subunits:groEL oligomer) of chaperonins. When a stable groEL-GS complex, formed under optimal conditions, was concentrated 4-fold by centrifugal ultrafiltration prior to ATP addition, the amount of total active GS (percent of the original activity) recovered remained at optimal levels and no longer showed a concentration-dependent decline. The GS subunits that are initially bound and then released from groEL by ATP are assembly-competent. It is proposed that the subunits are no longer able to kinetically equilibrate with folding intermediates that misfold or aggregate. If a stable groEL-protein substrate complex can be amassed without loss of activity, this will facilitate studies on molecular aspects of chaperonin release mechanisms and oligomeric protein assembly.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				J. L. Chuang, R. M. Wynn, J.-L. Song, and D. T. Chuang GroEL/GroES-dependent Reconstitution of alpha 2beta 2 Tetramers of Human Mitochondrial Branched Chain alpha -Ketoacid Decarboxylase. OBLIGATORY INTERACTION OF CHAPERONINS WITH AN alpha beta DIMERIC INTERMEDIATE J. Biol. Chem., April 9, 1999; 274(15): 10395 - 10404. [Abstract] [Full Text] [PDF]

				K. E. Smith and M. T. Fisher Interactions between the GroE Chaperonins and Rhodanese J. Biol. Chem., September 15, 1995; 270(37): 21517 - 21523. [Abstract] [Full Text] [PDF]