Crystallization and preliminary X-ray crystallographic analysis of a putative nonribosomal peptide synthase AmbB fromPseudomonas aeruginosa

Abstract

AmbB is a putative nonribosomal peptide synthase from Pseudomonas aeruginosa, which is involved in the production of IQS, a potent cell-cell communication signal molecule that integrates the quorum-sensing mechanism and stress response. It consists of 1249 amino acids and contains an AMPbinding domain, a phosphopantetheine-binding (PB) domain and a condensation (C) domain. In this report, a truncated form of AmbB that contains the PB domain and the condensation domain was overexpressed with an N-terminal GST tag in Escherichia coli and purified as a monomer using affinity and size-exclusion chromatography. The recombinant AmbBc (comprising residues 727-1249 of full-length AmbB) was crystallized using the hanging-drop vapourdiffusion method and a full data set was collected to 2.45 Å resolution using a synchrotron-radiation source. The crystals belonged to space group P6 1 22 or P6 5 22, with unit-cell parameters a = b = 87.81, c = 286.8 Å , = 90, = 90, = 120 , and contained one molecule per asymmetric unit.