Crystallization and preliminary X‐ray analysis of recombinant glutamate mutase and of the isolated component S from Clostridium cochlearium

Glutamate mutase [(B12)1] was reconstituted by incubating purified components E () and S () from Clostridium cochlearium, both produced in Escherichia coli, with either aquo‐ or cyanocobalamin. The inactive glutamate mutase obtained was crystallized with polyethyleneglycol 4000 as precipitant. Crystals are monoclinic with space group P21and have cell dimensions a= 64.6, b= 113.2, c= 108.4 Å and β = 96.0° for the glutamate mutase reconstituted with aquocobalamin. They diffract to a resolution of at least 2.7 Å. Isolated component S was crystallized in the presence of an excess of cyanocobalamin, yielding red crystals of space group I422 with unit‐cell dimensions of a= b= 69.9 and c= 107.1 Å. The crystals diffract to about 3.2 Å resolution. Native data sets were collected for both crystal forms.