Expression, crystallization and preliminary X-ray diffraction analysis of a modification subunit of a putative type I restriction enzyme from Vibrio vulnificus YJ016

Modification (HsdM) and specificity (HsdS) subunits are constituents of an active methyltransferase (MTase) of multifunctional type I restriction enzymes. To provide a molecular background on HsdM, a putative hsdM gene from Vibrio vulnificus YJ016 (HsdM_Vv) was cloned and the expressed protein was purified and crystallized from 22%(w/v) polyethylene glycol 8000, 0.02 M imidazole pH 7.5 and 5 mM β-mercaptoethanol. Diffraction data were collected to 1.86 Å resolution using synchrotron radiation. The crystal belonged to the tetragonal space group P4₁2₁2 or P4₃2₁2, with unit-cell parameters a = b = 78.9, c = 165.8 Å. With one molecule in the asymmetric unit, the crystal volume per unit protein weight was 2.12 ų Da⁻¹, with a solvent content of 42%.