Crystallization and preliminary X-ray studies of the protease domain of the heat-shock protein HtrA from Thermotoga maritima.

HtrA (high-temperature requirement A) is a widely distributed heat-shock protein which has both molecular-chaperone and proteolytic activities. It is composed of two PDZ domains essential for oligomerization and a protease domain. To understand the molecular basis of the dual function of HtrA, the protease domain of T. maritima HtrA has been crystallized. X-ray diffraction data have been collected to 2.7 A resolution using a synchrotron-radiation source. Crystals belong to the cubic space group P2(1)3, with unit-cell parameters a = b = c = 120.55 (8) A. The asymmetric unit contains two protease domains, with a corresponding V(M) of 2.80 A(3) Da(-1) and a solvent content of 56.1%.