Structure of the ThDP-dependent enzyme benzaldehyde lyase refined to 1.65 Å resolution

Benzaldehyde lyase (BAL; EC 4.1.2.38) is a thiamine diphosphate (ThDP) dependent enzyme that catalyses the enantioselective carboligation of two molecules of benzaldehyde to form (R)-benzoin. BAL has hence aroused interest for its potential in the industrial synthesis of optically active benzoins and derivatives. The structure of BAL was previously solved to a resolution of 2.6 angstrom using MAD experiments on a selenomethionine derivative [Mosbacher et al. (2005), FEBS J. 272, 6067-6076]. In this communication of parallel studies, BAL was crystallized in an alternative space group (P2(1)2(1)2(1)) and its structure refined to a resolution of 1.65 angstrom, allowing detailed observation of the water structure, active-site interactions with ThDP and also the electron density for the co-solvent 2-methyl-2,4-pentanediol (MPD) at hydrophobic patches of the enzyme surface.