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 Å resolution and refined to an R factor of 17.7% (Rfree = 23.8%). The enzyme belongs to the α+β class of proteins and the structure shows the typical papain-like fold composed of two domains, the α-helix-rich (L) domain and the β-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.
Original language | English |
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Article number | fw5124 |
Pages (from-to) | 555-563 |
Number of pages | 9 |
Journal | Acta Crystallographica Section D: Biological Crystallography |
Volume | 63 |
Issue number | 5 |
DOIs | |
State | Published - 21 Apr 2007 |
Keywords
- Cysteine proteases
- E-64
- Inhibitors
- Mexicain