Overexpression, purification, crystallization and preliminary X-ray crystallographic analysis of the periplasmic domain of outer membrane protein A from Acinetobacter baumannii

Abstract

Outer membrane protein A from Acinetobacter baumannii (AbOmpA) is a major outer membrane protein and a key player in the bacterial pathogenesis that induces host cell death. AbOmpA is presumed to consist of an N-terminal beta-barrel transmembrane domain and a C-terminal periplasmic OmpA-like domain. In this study, the recombinant C-terminal periplasmic domain of AbOmpA was overexpressed in Escherichia coli, purified and crystallized using the vapour-diffusion method. A native diffraction data set was collected to a resolution of 2.0 angstrom using synchrotron radiation. The space group of the crystal was P21, with unit-cell parameters a = 58.24, b = 98.59, c = 97.96 angstrom, beta = 105.92 degrees. The native crystal contained seven or eight molecules per asymmetric unit and had a calculated Matthews coefficient of 2.93 or 2.56 angstrom 3 Da-1.