Crystal structure of apo-glycolate oxidase.

The crystal structure of the apoform of the alpha/beta-barrel enzyme glycolate oxidase has been determined to 2.6 A resolution. Removal of the tightly bound cofactor FMN has a very strong influence on the protein structure; it is converted into a very flexible state, verging on a molten globule type of structure. The asymmetric unit contains two subunits with different conformations to each other and to the holo-enzyme. The secondary structures are preserved, but their mutual arrangement has changed to some extent introducing cavities into the protein. The largest structural shifts are, however, found in the loops.