Equilibrium unfolding and enzyme kinetics of chimeric mu class glutathionetransferases

Rat glutathione transferases, M1-1 and M2-2, share high sequence and struct ural similarities, yet they have different stabilities and efficiencies in nucleophilic aromatic substitutions (S,Ar). Chimeric mutants of M1-1 and M2 -2 were studied to better understand the structural basis for these differe nces; the chimera M12-12 contains domain I from M1 and domain II from M2 an d vice versa for M21-21. The results suggest that domain II is the major de terminant in quaternary structural stability and efficiency in S,AR reactio ns. Efforts are underway to identify interactions, which may contribute to these differences. (C) 2001 Elsevier Science Ireland Ltd. All rights reserv ed.