Crystallization and preliminary X-ray analysis of Weissella viridescens FemX UDP-MurNAc-pentapeptide: L -alanine ligase
Résumé
Synthesis of the cell-wall peptidoglycan of firmicutes involves a unique family of peptide-bond-forming enzymes that use amino-acyl-tRNAs as substrates and are referred to as Fem proteins as they are factors essential for methicillin resistance in Staphylococcus aureus. The FemX UDP-MurNAc-pentapeptide:l-alanine ligase of Weissella viridescens was overexpressed, purified and crystallized. Native data were collected to 1.7 A resolution. The crystals belong to space group P2(1), with unit-cell parameters a = 42.03, b = 99.92, c = 45.84 A, beta = 116.02 degrees. The asymmetric unit contains one molecule. A selenium-derivative data set has been collected to 2.1 A resolution at the peak wavelength of the selenium absorption edge. Six strong selenium positions were visible in the anomalous Patterson map. Three additional weaker Se atoms have been identified by anomalous Fourier synthesis.