Figure 1

Structure-based alignment of alanine racemasesfrom B. anthracis (AlrBax), G. stearothermophilus (AlrGst), M. tuberculosis (AlrMtb), S. lavendulae (AlrSla) and P. aeruginosa (DadXPao). The initial alignment was performed using EXPRESSO (3DCoffee) [63] and adjusted manually upon inspection of the superimposed structures. An asterisk marks the location of the Lys residue bound to PLP, the diamond marks the location of the Tyr residue that functions as the second base in the racemase reaction, a bullet denotes the location of the carbamylated lysine found in other alanine racemase structures and replaced by a chloride ion on Alr _Bax . I and M denote residues found in the middle or the inner layer of the active site entryway along with their position in the entryway.