Premium
A surface mutant (G82R) of a human α‐glutathione S‐transferase shows decreased thermal stability and a new mode of molecular association in the crystal
Author(s) -
Zeng Ke,
Rose John P.,
Chen HongChi,
Strickland Corey L.,
Tu ChenPei D.,
Wang BiCheng
Publication year - 1994
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/prot.340200306
Subject(s) - thermostability , mutant , dimer , crystallography , chemistry , salt bridge , thermal stability , glutathione , crystal structure , transferase , residue (chemistry) , enzyme , biochemistry , organic chemistry , gene
A chimeric enzyme (GST121) of the human α‐glutathione S‐transferases GST1‐1 and GST2‐2, which has improved catalytic efficiency and thermostability from its wild‐type parent proteins, has been crystallized in a space group that is isomorphous with that reported for crystals of GST1‐1. However, a single‐site (G82R) mutant of GST121, which exhibits a significant reduction both in vitro and in vivo in protein thermostability, forms crystals that are not isomorphous with GST1‐1. The mutant protein crystallizes in space group P2 1 2 1 2 1 , with cell dimensions a = 49.5, b = 92.9, c = 115.9 Å, and one dimer per asymmetric unit. Preliminary crystallographic results show that a mutation of the surface residue Gly 82 from a neutral to a charged residue causes new salt bridges to be formed among the GST dimers, suggesting that the G82R mutant might aggregate more readily than does GST121 in solution resulting in a change of its solution properties. © 1994 Wiley‐Liss, Inc.