glutamate mutase ( EC 5.4.99.1 ). [ 4 ] Prokaryotic methyleneglutarate mutase ( EC 5.4.99.4 ). Prokaryotic isobutyryl-CoA mutase ( EC 5.4.99.13 ). The core structure of the cobalamin-binding domain is characterised by a five-stranded alpha/beta (Rossmann) fold, which consists of 5 parallel beta-sheets surrounded by 4-5 alpha helices in three