A study in molecular contingency: glutamine phosphoribosylpyrophosphate amidotransferase is a promiscuous and evolvable phosphoribosylanthranilate isomerase.

ABSTRACT: The prevalence of paralogous enzymes implies that novel catalytic functions can evolve on preexisting protein scaffolds. The weak secondary activities of proteins, which reflect catalytic promiscuity and substrate ambiguity, are plausible starting points for this evolutionary process. In this study, we observed the emergence of a new enzyme from the ASKA (A Complete Set of E. coli K-12 ORF Archive) collection of Escherichia coli open reading frames. The overexpression of (His)(6)-tagged glutamine phosphoribosylpyrophosphate amidotransferase (PurF) unexpectedly rescued a Delta trpF E. coli strain from starvation on minimal media. The wild-type PurF and TrpF enzymes are unrelated in sequence, tertiary structure and catalytic mechanism. The promiscuous phosphoribosylanthranilate isomerase act

SUBMITTER: Patrick WM 

PROVIDER: S-EPMC2292674 | biostudies-literature | 2008 Mar

REPOSITORIES: biostudies-literature