While rabbit muscle phosphoglucomutase has served as the prototype for much of the elucidation of this enzyme's structure, newer bacterium-derived crystal structures exhibit many of the same defining characteristics [REF].
Each monomer comprises four distinct α/β structural units, each of which contains one of the four strands in each monomer's β-sheet and is made up only of the residues in a given sequence domain (see image at right) [REF].