Purification, crystallization and preliminary X-ray diffraction analysis of human enolase-phosphatase E1.

Enolase-phosphatase E1 (MASA) is a bifunctional enzyme in the ubiquitous methionine-salvage pathway and catalyzes the continuous reaction of 2,3-diketo-5-methylthio-1-phosphopentane to yield the acireductone metabolite. Recombinant human E1 enzyme has been crystallized using the hanging-drop vapour-diffusion method and diffraction-quality crystals were grown at 291 K using PEG 4000 as precipitant. Diffraction data were collected to 1.7 A resolution from SeMet-derivative crystals at 100 K using synchrotron radiation. The crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 54.02, b = 57.55, c = 87.32 A. The structure was subsequently solved by the multi-wavelength anomalous diffraction (MAD) phasing method.