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Hydrophobic dye inhibits aggregation of molten carbonic anhydrase during thermal unfolding and refolding
Author(s) -
Kundu Bishwajit,
Guptasarma Purnananda
Publication year - 1999
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/(sici)1097-0134(19991115)37:3<321::aid-prot1>3.0.co;2-l
Subject(s) - chemistry , intermolecular force , carbonic anhydrase , molten globule , hydrophobic effect , protein folding , intramolecular force , protein aggregation , biophysics , chaperone (clinical) , carbonic anhydrase ii , heat shock protein , hydrogen bond , crystallography , biochemistry , enzyme , stereochemistry , organic chemistry , molecule , medicine , pathology , gene , biology
Association‐seeking surfaces on partially structured polypeptides can participate in interactions that are either intramolecular (folding related) or intermolecular (aggregative). During heat shock, intermolecular associations leading to aggregation are prevented through the binding of such surfaces by chaperones of the Hsp20 family (with Hsp70 later effecting release and refolding). Here we report that the hydrophobic dye, 8‐anilino‐1‐naphthalenesulfonate (ANS), mimics the function of the chaperones in its interactions with molten carbonic anhydrase (CA). At 150‐fold molar excess of dye over protein, heat‐induced aggregation of CA is almost completely inhibited by binding of ANS to solvent‐exposed clusters of nonpolar residues. After exposure of ANS‐containing protein solutions to temperatures as high as 95°C, refolded CA can be recovered through cooling and dialysis, with no accompanying aggregation. This apparent mimicking of chaperone activity by a small dye opens up new approaches to understanding and manipulating protein aggregation. Proteins 1999;37:321–324. ©1999 Wiley‐Liss, Inc.