Overproduction, purification, crystallization and preliminary X-ray diffraction analysis of YopM, an essential virulence factor extruded by the plague bacterium Yersinia pestis.

A recombinant form of Yersinia pestis YopM with a C-terminal polyhistidine affinity tag has been overproduced in Escherichia coli, purified to homogeneity and crystallized using the hanging-drop vapor-diffusion technique. Several different crystal forms were obtained. The most suitable crystals for X-ray diffraction belonged to space groups P4(2)22 (unit-cell parameters a = 109.36, b = 109.36, c = 101.50 A) and C222(1) (unit-cell parameters a = 71.73, b = 121. 85, c = 189.79 A). With a synchrotron-radiation source, these crystals diffracted to 2.4 and 1.9 A resolution, respectively.