Open AccessHistidine 109 in peptidyl‐prolyl cis‐trans isomerase of Bacillus subtilis plays an important role in catalysis and in cyclosporin A binding
Author(s) -
Achenbach Tatjana V.,
Göthel Sven F.,
Marahiel Mohamed A.
Publication year - 1997
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1997.tb12635.x
Subject(s) - bacillus subtilis , isomerase , peptidylprolyl isomerase , enzyme kinetics , cis trans isomerases , histidine , enzyme , stereochemistry , mutant , chemistry , cyclophilin , biochemistry , prolyl isomerase , active site , wild type , biology , pin1 , bacteria , genetics , gene
The cyclophilin of Bacillus subtilis has a moderate affinity to cyclosporin A (IC 50 : 120 nM) and low catalytic activity ( k cat / K m : 1.1 μM −1 s −1 ) when compared to other ubiquitous peptidyl‐prolyl cis‐trans isomerases (PPIases). The active site residues V52, H90 and H109, which are not conserved within other peptidyl‐prolyl cis‐trans isomerases, were found to play an important role in cyclosporin A binding and catalytic activity. In this work we report on double mutations of these residues, which greatly improved cyclosporin A affinity and catalytic activity. The H90N/H109W mutation displayed an IC 50 value of 46 nM whereas the V52M/H109F mutation exhibited over 18‐fold higher catalytic activity than that detected for wild‐type PPIase. The mutations H109W and H109F of the B. subtilis PPIase showed no change in cyclosporin A affinity and catalytic activity between pH 6 and 8. In contrast, wild‐type PPIase (H109) showed up to 10‐fold reduction below pH 7.5, both in cyclosporin A affinity and in catalytic activity. These findings clearly underline the importance of the unique H109 residue in the B. subtilis enzyme.