Contribution of the two conserved tryptophan residues to the catalytic and structural properties of Proteus mirabilis glutathione S-transferase B1-1.

ABSTRACT: PmGSTB1-1 (Proteus mirabilis glutathione S-transferase B1-1) has two tryptophan residues at positions 97 and 164 in each monomer. Structural data for this bacterial enzyme indicated that Trp97 is positioned in the helix a4, whereas Trp164 is located at the bottom of the helix a6 in the xenobiotic-binding site. To elucidate the role of the two tryptophan residues they were replaced by site-directed mutagenesis. Trp97 and Trp164 were mutated to either phenylalanine or alanine. A double mutant was also constructed. The effects of the replacement on the activity, structural properties and antibiotic-binding capacity of the enzymes were examined. On the basis of the results obtained, Trp97 does not seem to be involved in the enzyme active site and structural stabilization. In contrast, differen

SUBMITTER: Allocati N 

PROVIDER: S-EPMC1134671 | biostudies-literature | 2005 Jan

REPOSITORIES: biostudies-literature