Crystallographic analysis of phosphoglycerate kinase from the hyperthermophilic bacterium Thermotoga maritima.

Phosphoglycerate kinase from the hyperthermophilic bacterium Thermotoga maritima has been co-crystallized with its substrate 3-phosphoglycerate and the ATP analogue AMP-PNP using the vapour diffusion method. Crystals were obtained from a solution containing polyethylene glycol (MW 3000/8000) as precipitating agent. A complete diffraction data set from orthorhombic crystals was collected up to 2.0 Angstrom resolution. The TmPGK crystallizes in the space group P2(1)2(1)2 (cell dimensions: a = 62.0 Angstrom, b = 76.9 Angstrom, c = 87.5 Angstrom) with one molecule in the asymmetric unit. The structure was solved by Patterson search methods using Bacillus stearothermophilus PGK as a search model and was refined to a crystallographic R factor of 22.0%. Compared to the enzyme from B. stearothermophilus, horse, pig and yeast, the Thermotoga enzyme exhibits a drastically reduced interdomain angle, similar to the one reported for PGK from Trypanosoma brucei. Here we present crystallographic data of the first high-resolution structure of a PCK in largely closed conformation, complexed with the two products of the catalyzed reaction, and, at the same time, the first PGK structure from a hyperthermophilic organism.