1aec
From Proteopedia
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CRYSTAL STRUCTURE OF ACTINIDIN-E-64 COMPLEX+
Overview
E-64, 1-(L-trans-epoxysuccinylleucylamino)-4-guanidinobutane, is a potent and highly selective irreversible inhibitor of cysteine proteases. The crystal structure of a complex of actinidin and E-64 has been determined at 1.86-A resolution by using the difference Fourier method and refined to an R-factor of 14.5%. The electron density map clearly shows that the C2 atom of the E-64 epoxide ring is covalently bonded to the S atom of the active-site cysteine 25. The charged carboxyl group of E-64 forms four H-bonds with the protein and thus may play an important role in favorably positioning the inhibitor molecule for nucleophilic attack by the active-site thiolate anion. The interaction features between E-64 and actinidin are very similar to those seen in the papain-E-64 complex; however, the amino-4-guanidinobutane group orients differently. The crystals of the actinidin-E-64 complex diffracted much better than the papain-E-64 complex, and consequently the present study provides more precise geometrical information on the binding of the inhibitor. Moreover, this study provides yet another confirmation that the binding of E-64 is at the S subsites and not at the S' subsites as has been previously proposed. The original actinidin structure has been revised using the new cDNA sequence information.
About this Structure
1AEC is a Single protein structure of sequence from Actinidia chinensis with as ligand. Active as Actinidain, with EC number 3.4.22.14 Full crystallographic information is available from OCA.
Reference
Crystal structure of an actinidin-E-64 complex., Varughese KI, Su Y, Cromwell D, Hasnain S, Xuong NH, Biochemistry. 1992 Jun 9;31(22):5172-6. PMID:1606141
Page seeded by OCA on Thu Feb 21 11:43:35 2008
