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From Proteopedia
CRUZAIN INHIBITED BY BENZOYL-TYROSINE-ALANINE-FLUOROMETHYLKETONE
Structural highlights
FunctionCYSP_TRYCR Hydrolyzes chromogenic peptides at the carboxyl Arg or Lys; requires at least one more amino acid, preferably Arg, Phe, Val or Leu, between the terminal Arg or Lys and the amino-blocking group. The cysteine protease may play an important role in the development and differentiation of the parasites at several stages of their life cycle. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe structure of cruzain, an essential protease from the parasite Trypanosoma cruzi, was determined by X-ray crystallography bound to two different covalent inhibitors. The cruzain S2 specificity pocket is able to productively bind both arginine and phenylalanine residues. The structures of cruzain bound to benzoyl-Arg-Ala-fluoromethyl ketone and benzoyl-Tyr-Ala-fluoromethyl ketone at 2.2 and 2.1 A, respectively, show a pH-dependent specificity switch. Glu 205 adjusts to restructure the S2 specificity pocket, conferring right binding to both hydrophobic and basic residues. Kinetic analysis of activated peptide substrates shows that substrates placing hydrophobic residues in the specificity pocket are cleaved at a broader pH range than hydrophilic substrates. These results demonstrate how cruzain binds both basic and hydrophobic residues and could be important for in vivo regulation of cruzain activity. Structural determinants of specificity in the cysteine protease cruzain.,Gillmor SA, Craik CS, Fletterick RJ Protein Sci. 1997 Aug;6(8):1603-11. PMID:9260273[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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