title: Structure of the mexicain-E-64 complex and comparison with other cysteine proteases of the papain family.
abstract: Mexicain is a 23.8 kDa cysteine protease from the tropical plant Jacaratia mexicana. It is isolated as the most abundant product after cation-exchange chromatography of the mix of proteases extracted from the latex of the fruit. The purified enzyme inhibited with E-64 [N-(3-carboxyoxirane-2-carbonyl)-leucyl-amino(4-guanido)butane] was crystallized by sitting-drop vapour diffusion and the structure was solved by molecular replacement at 2.1 A resolution and refined to an R factor of 17.7% (R(free) = 23.8%). The enzyme belongs to the alpha+beta class of proteins and the structure shows the typical papain-like fold composed of two domains, the alpha-helix-rich (L) domain and the beta-barrel-like (R) domain, separated by a groove containing the active site formed by residues Cys25 and His159, one from each domain. The four monomers in the asymmetric unit show one E-64 molecule covalently bound to Cys25 in the active site and differences have been found in the placement of E-64 in each monomer.
authors: Laboratorio de Estudios Cristalográficos, IACT, CSIC-Universidad de Granada, Granada, Spain.
authors: J A
authors: JA
authors: Gavira
authors: L A
authors: LA
authors: González-Ramírez
authors: M C
authors: MC
authors: Oliver-Salvador
authors: M
authors: M
authors: Soriano-García
authors: J M
authors: JM
authors: García-Ruiz
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003460:Crystallization; D003461:Crystallography; D004591:Electrophoresis, Polyacrylamide Gel; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010206:Papain / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
chemical_list: D010206:Papain