title: Structure of hydroxynitrile lyase from Manihot esculenta in complex with substrates acetone and chloroacetone: implications for the mechanism of cyanogenesis.
abstract: The crystal structures of hydroxynitrile lyase from Manihot esculenta (MeHNL) complexed with the native substrate acetone and substrate analogue chloroacetone have been determined and refined at 2.2 A resolution. The substrates are positioned in the active site by hydrogen-bond interactions of the carbonyl O atom with Thr11 OG, Ser80 OG and, to a lesser extent, Cys81 SG. These studies support a mechanism for cyanogenesis as well as for the stereospecific MeHNL-catalyzed formation of (S)-cyanohydrins, which closely resembles the base-catalyzed chemical reaction of HCN with carbonyl compounds.
authors.affiliation: Universität Stuttgart, Institut für Organische Chemie, Pfaffenwaldring 55, D-70569 Stuttgart, Germany. peterlauble@t-online.de
authors.forename: H
authors.initials: H
authors.lastname: Lauble
authors.forename: S
authors.initials: S
authors.lastname: Förster
authors.forename: B
authors.initials: B
authors.lastname: Miehlich
authors.forename: H
authors.initials: H
authors.lastname: Wajant
authors.forename: F
authors.initials: F
authors.lastname: Effenberger
mesh_terms: D000096:Acetone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism*; D000446:Aldehyde-Lyases / Q000737:chemistry* / Q000378:metabolism*; D003460:Crystallization; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D019685:Rosales / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D011994:Recombinant Proteins; D000096:Acetone; C006973:chloroacetone; D000446:Aldehyde-Lyases; C079359:hydroxymandelonitrile lyase