Lysine relay mechanism coordinates intermediate transfer in vitamin B6 biosynthesis.

ABSTRACT: Substrate channeling has emerged as a common mechanism for enzymatic intermediate transfer. A conspicuous gap in knowledge concerns the use of covalent lysine imines in the transfer of carbonyl-group-containing intermediates, despite their wideuse in enzymatic catalysis. Here we show how imine chemistry operates in the transfer of covalent intermediates in pyridoxal 5'-phosphate biosynthesis by the Arabidopsis thaliana enzyme Pdx1. An initial ribose 5-phosphate lysine imine is converted to the chromophoric I₃₂₀ intermediate, simultaneously bound to two lysine residues and partially vacating the active site, which creates space for glyceraldehyde 3-phosphate to bind. Crystal structures show how substrate binding, catalysis and shuttling are coupled to conformational changes aroun

SUBMITTER: Rodrigues MJ 

PROVIDER: S-EPMC6078385 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature