1l5a

Publication Abstract from PubMed

Nonribosomal peptide synthetases (NRPSs) are large, multidomain enzymes that biosynthesize medically important natural products. We report the crystal structure of the free-standing NRPS condensation (C) domain VibH, which catalyzes amide bond formation in the synthesis of vibriobactin, a Vibrio cholerae siderophore. Despite low sequence identity, NRPS condensation enzymes are structurally related to chloramphenicol acetyltransferase (CAT) and dihydrolipoamide acyltransferases. However, although the latter enzymes are homotrimers, VibH is a monomeric pseudodimer. The VibH structure is representative of both NRPS condensation and epimerization domains, as well as the condensation-variant cyclization domains, which are all expected to be monomers. Surprisingly, despite favorable positioning in the active site, a universally conserved histidine important in CAT and in other C domains is not critical for general base catalysis in VibH.

The structure of VibH represents nonribosomal peptide synthetase condensation, cyclization and epimerization domains.,Keating TA, Marshall CG, Walsh CT, Keating AE Nat Struct Biol. 2002 Jul;9(7):522-6. PMID:12055621^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.