Crystallization and preliminary X‐ray crystallographic studies of a PduO‐type ATP:cob(I)alamin adenosyltransferase from Bacillus cereus

Cobalamin adenosyltransferases transfer a 5′‐deoxyadenosyl moiety from ATP and covalently attach it to the cobalt(I) ion of the corrin ring of cobalamin to generate adenosylcobalamin. The PduO‐type adenosyltransferase from Bacillus cereus was overexpressed in Escherichia coli , purified and crystallized as the apoenzyme as well as in complex with Mg 2+ and ATP (MgATP). Diffraction data were collected to 1.9 Å resolution for the native crystals and 2.0 Å resolution for the complexed crystals. Both crystals belonged to the orthorhombic space group C 222 1 ; the native crystals have unit‐cell parameters a = 64.93, b = 137.08, c  = 158.55 Å. The asymmetric unit contained one trimer, with a corresponding V M of 2.69 Å 3  Da −1 .