Structure of the mexicain-E-64 complex and comparison with other cysteine proteases of the papain family.
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.
Gavira
J A
JA
Laboratorio de Estudios Cristalográficos, IACT, CSIC-Universidad de Granada, Granada, Spain.
González-Ramírez
L A
LA
Oliver-Salvador
M C
MC
Soriano-García
M
M
García-Ruiz
J M
JM
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
D010206:Papain