1aec
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(New page: 200px<br /><applet load="1aec" size="450" color="white" frame="true" align="right" spinBox="true" caption="1aec, resolution 1.86Å" /> '''CRYSTAL STRUCTURE OF...)
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Revision as of 08:40, 20 November 2007
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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 E64 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
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