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The structure of native G‐actin
Author(s) -
Wang Hui,
Robinson Robert C.,
Burtnick Leslie D.
Publication year - 2010
Publication title -
cytoskeleton
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 86
eISSN - 1949-3592
pISSN - 1949-3584
DOI - 10.1002/cm.20458
Subject(s) - actin , actin binding protein , polymerization , biophysics , biology , atp hydrolysis , actin remodeling , microfilament , protein structure , biochemistry , heat shock protein , protein folding , conformational change , crystallography , cytoskeleton , polymer , actin cytoskeleton , chemistry , enzyme , atpase , cell , organic chemistry , gene
Heat shock proteins act as cytoplasmic chaperones to ensure correct protein folding and prevent protein aggregation. The presence of stoichiometric amounts of one such heat shock protein, Hsp27, in supersaturated solutions of unmodified G‐actin leads to crystallization, in preference to polymerization, of the actin. Hsp27 is not evident in the resulting crystal structure. Thus, for the first time, we present the structure of G‐actin in a form that is devoid of polymerization‐deterring chemical modifications or binding partners, either of which may alter its conformation. The structure contains a calcium ion and ATP within a closed nucleotide‐binding cleft, and the D‐loop is disordered. This native G‐actin structure invites comparison with the current F‐actin model in order to understand the structural implications for actin polymerization. In particular, this analysis suggests a mechanism by which the bound cation coordinates conformational change and ATP‐hydrolysis. © 2010 Wiley‐Liss, Inc.