Histidine 109 in peptidyl-prolyl cis-trans isomerase of Bacillus subtilis plays an important role in catalysis and in cyclosporin A binding.
FEMS Microbiol Lett
; 154(1): 139-44, 1997 Sep 01.
Article
en En
| MEDLINE
| ID: mdl-9297832
The cyclophilin of Bacillus subtilis has a moderate affinity to cyclosporin A (IC50: 120 nM) and low catalytic activity (Kcat/ Km: 1.1 microM-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 IC50 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.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Bacillus subtilis
/
Ciclosporina
/
Isomerasa de Peptidilprolil
/
Histidina
Idioma:
En
Revista:
FEMS Microbiol Lett
Año:
1997
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Reino Unido