Cα-atom superpositions of AlrSas and other alanine racemases. S. aureus, green; G. stearothermophilus, blue; B. anthracis, red; M. tuberculosis, orange; P. aeruginosa, purple. Cα-atom traces showing superpositions between the (a) N-terminal and (b) C-terminal domains. Regions corresponding to significant structural deviations and their location in the AlrSas structure are labelled. (c) Superposition of the N-terminal α/β-barrel domain of whole alanine racemase monomers visualized as a ribbon representation. The PLP cofactor of AlrSas is depicted as a black stick model.