Enzyme adaptation to alkaline pH: atomic resolution (1.08 A) structure of phosphoserine aminotransferase from Bacillus alcalophilus.

ABSTRACT: The crystal structure of the vitamin B(6)-dependent enzyme phosphoserine aminotransferase from the obligatory alkaliphile Bacillus alcalophilus has been determined at 1.08 A resolution. The model was refined to an R-factor of 11.7% (R(free) = 13.9%). The enzyme displays a narrow pH optimum of enzymatic activity at pH 9.0. The final structure was compared to the previously reported structure of the mesophilic phosphoserine aminotransferase from Escherichia coli and to that of phosphoserine aminotransferase from a facultative alkaliphile, Bacillus circulans subsp. alkalophilus. All three enzymes are homodimers with each monomer comprising a two-domain architecture. Despite the high structural similarity, the alkaliphilic representatives possess a set of distinctive structural features. Two r

SUBMITTER: Dubnovitsky AP 

PROVIDER: S-EPMC2253317 | biostudies-literature | 2005 Jan

REPOSITORIES: biostudies-literature