Insights to the Structural Basis for the Stereospecificity of the Escherichia coli Phytase, AppA.

ABSTRACT: AppA, the Escherichia coli periplasmic phytase of clade 2 of the histidine phosphatase (HP2) family, has been well-characterized and successfully engineered for use as an animal feed supplement. AppA is a 1D-6-phytase and highly stereospecific but transiently accumulates 1D-myo-Ins(2,3,4,5)P₄ and other lower phosphorylated intermediates. If this bottleneck in liberation of orthophosphate is to be obviated through protein engineering, an explanation of its rather rigid preference for the initial site and subsequent cleavage of phytic acid is required. To help explain this behaviour, the role of the catalytic proton donor residue in determining AppA stereospecificity was investigated. Four variants were generated by site-directed mutagenesis of the active site HDT am

SUBMITTER: Acquistapace IM 

PROVIDER: S-EPMC9181005 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature