The Y430F mutant of Salmonella d-ornithine/d-lysine decarboxylase has altered stereospecificity and a putrescine allosteric activation site.

ABSTRACT: Tyrosine-430 of d-ornithine/d-lysine decarboxylase (DOKDC) is located in the active site, and was suggested to be responsible for the D-stereospecificity of the enzyme. We have prepared the Y430F mutant form of Salmonella enterica serovar typhimurium DOKDC and evaluated its catalytic activity with D- and l-lysine and ornithine. The kinetic results show that the Y430F mutant has measurable decarboxylase activity with both D- and l-lysine and ornithine, which wild type DOKDC does not. Spectroscopic experiments show that these amino acids bind to form external aldimine complexes with the pyridoxal-5'-phosphate with λ_max = 425 nm. In addition, we have obtained crystal structures of Y430F DOKDC bound to HEPES, putrescine, d-ornithine, d-lysine, and d-arginine. The d-amino acids bind

SUBMITTER: Phillips RS 

PROVIDER: S-EPMC10351609 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature