Purification, crystallization and preliminary crystallographic study of the putative enolase MJ0232 from the hyperthermophilic archaeon Methanococcus jannaschii

Enolase is a glycolytic enzyme that catalyzes the interconversion of phosphoenolpyruvate and 2-phosphoglycerate. In order to gain insight into the biological significance of the oligomeric state of this enzyme, the putative enolase MJ0232 from the hyperthermophilic archaeon Methanococcus jannaschii was cloned, overexpressed and purified. Crystals were obtained by the oil-microbatch method at 291 K using PEG 4000 as a precipitant. A native data set was collected to 1.85 angstrom resolution. The crystal belonged to the tetragonal space group I4, with unit-cell parameters a = 148.8, c = 91.2 angstrom. An initial model was obtained by molecular replacement, which revealed an octameric subunit association (a tetramer of dimers). This result is consistent with that from a dynamic light-scattering experiment, suggesting biological relevance of the octameric state of MJ0232 in solution.