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

J. Biol. Chem., Vol. 275, Issue 25, 18623-18637, June 23, 2000

This Article Full Text Full Text (PDF) All Versions of this Article: 275/25/18623    most recent M000470200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map 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 Google Scholar Google Scholar Articles by Champeil, P. Articles by le Maire, M. Search for Related Content PubMed PubMed Citation Articles by Champeil, P. Articles by le Maire, M. Social Bookmarking                      What's this?

Interaction of Amphipols with Sarcoplasmic Reticulum Ca²⁺-ATPase^*

Philippe Champeil^§, Thierry Menguy, Christophe Tribet^¶, Jean-Luc Popot, and Marc le Maire

From the  Unité de Recherche Associée 2096 (CNRS et CEA) and Section de Biophysique des Protéines et des Membranes, Département de Biologie Cellulaire et Moléculaire, Commissariat à l'Energie Atomique Saclay, 91191 Gif-sur-Yvette Cedex, the ^¶ Unité Mixte de Recherche 7615 (CNRS, Université Paris VI & Ecole Supérieure de Physique et Chimie Industrielles de la Ville de Paris), 10 rue Vauquelin, 75231 Paris Cedex 05, and  Unité Propre de Recherche 9052 (CNRS), Institut de Biologie Physico-Chimique, 11 rue Pierre et Marie Curie, 75005 Paris, France

Amphipols are short-chain amphipathic polymers designed to keep membrane proteins soluble in aqueous solutions. We have evaluated the effects of the interaction of amphipols with sarcoplasmic reticulum Ca²⁺-ATPase either in a membrane-bound or a soluble form. If the addition of amphipols to detergent-solubilized ATPase was followed by removal of detergent, soluble complexes formed, but these complexes retained poor ATPase activity, were not very stable upon long incubation periods, and at high concentrations they experienced aggregation. Nevertheless, adding excess detergent to diluted detergent-free ATPase-amphipol complexes incubated for short periods immediately restored full activity to these complexes, showing that amphipols had protected solubilized ATPase from the rapid and irreversible inactivation that otherwise follows detergent removal. Amphipols also protected solubilized ATPase from the rapid and irreversible inactivation observed in detergent solutions if the ATPase Ca²⁺ binding sites remain vacant. Moreover, in the presence of Ca²⁺, amphipol/detergent mixtures stabilized concentrated ATPase against inactivation and aggregation, whether in the presence or absence of lipids, for much longer periods of time (days) than detergent alone. Our observations suggest that mixtures of amphipols and detergents are promising media for handling solubilized Ca²⁺-ATPase under conditions that would otherwise lead to its irreversible denaturation and/or aggregation.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati