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A single amino acid residue is responsible for species‐specific incompatibility between CCT and α‐actin
Author(s) -
Altschuler G.M.,
Dekker C.,
McCormack E.A.,
Morris E.P.,
Klug D.R.,
Willison K.R.
Publication year - 2009
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2009.01.031
Subject(s) - chaperonin , actin , yeast , biochemistry , saccharomyces cerevisiae , actin binding protein , biology , mutant , chaperone (clinical) , microbiology and biotechnology , gene isoform , protein folding , gene , actin cytoskeleton , cytoskeleton , cell , medicine , pathology
Actin is dependent on the type‐II chaperonin CCT (chaperonin containing TCP‐1) to reach its native state. In vitro, yeast CCT folds yeast and also mammalian cytoplasmic (β/γ) actins but is now found to be incapable of folding mammalian skeletal muscle α‐actin. Arrest of α‐actin on yeast CCT at a folding cycle intermediate has been observed by electron microscopy. This discovery explains previous observations in vivo that yeast mutants expressing only the muscle actin gene are non‐viable. Mutational analysis identified a single specific α‐actin residue, Asn‐297, that confers this species/isoform folding specificity. The implications of this incompatibility for chaperonin mechanism and actin–CCT co‐evolution are discussed.