1ppk
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CRYSTALLOGRAPHIC ANALYSIS OF TRANSITION STATE MIMICS BOUND TO PENICILLOPEPSIN: PHOSPHOROUS-CONTAINING PEPTIDE ANALOGUES
OverviewOverview
The molecular structures of three phosphorus-based peptide inhibitors of, aspartyl proteinases complexed with penicillopepsin [1, Iva-L-Val-L-Val-StaPOEt [Iva = isovaleryl, StaP = the phosphinic acid, analogue of statine [(S)-4-amino-(S)-3-hydroxy-6-methylheptanoic acid], (IvaVVStaPOEt)]; 2, Iva-L-Val-L-Val-L-LeuP-(O)Phe-OMe [LeuP = the, phosphinic acid analogue of L-leucine; (O)Phe = L-3-phenyllactic acid; OMe, = methyl ester] [Iva VVLP(O)FOMe]; and 3, Cbz-L-Ala-L-Ala-L-LeuP-(O)-Phe-OMe (Cbz = benzyloxycarbonyl), [CbzAALP(O)FOMe]] have been determined by X-ray crystallography and, refined to crystallographic agreement factors, R ( = sigma parallel to F0, magnitude of - Fc parallel to/sigma magnitude of F0), of 0.132, 0.131, and, 0.134, respectively. These inhibitors were designed to be structural, mimics of the tetrahederal transition-state intermediate encountered, during aspartic proteinase catalysis. They are potent inhibitors of, penicillopepsin with Ki values of 1, 22 nM; 2, 2.8 nM; and 3, 1600 nM, respectively [Bartlett, P. A., Hanson, J. E., & Giannousis, P. P. (1990), J. Org. Chem. 55, 6268-6274]. All three of these phosphorus-based, inhibitors bind virtually identically in the active site of, penicillopepsin in a manner that closely approximates that expected for, the transition state [James, M. N. G., Sielecki, A.R., Hayakawa, K., &, Gelb, M. H. (1992) Biochemistry 31, 3872-3886]. The pro-S oxygen atom of, the two phosphonate inhibitors and of the phosphinate group of the StaP, inhibitor make very short contact distances (approximately 2.4 A) to the, carboxyl oxygen atom, O delta 1, of Asp33 on penicillopepsin. We have, interpreted this distance and the stereochemical environment of the, carboxyl and phosphonate groups in terms of a hydrogen bond that most, probably has a symmetric single-well potential energy function. The pro-R, oxygen atom is the recipient of a hydrogen bond from the carboxyl group of, Asp213. Thus, we are able to assign a neutral status to Asp213 and a, partially negatively charged status to Asp33 with reasonable confidence., Similar very short hydrogen bonds involving the active site glutamic acid, residues of thermolysin and carboxypeptidase A and the pro-R oxygen of, bound phosphonate inhibitors have been reported [Holden, H. M., Tronrud, D. E., Monzingo, A. F., Weaver, L. H., & Matthews, B. W. (1987), Biochemistry 26, 8542-8553; Kim, H., & Lipscomb, W. N. (1991) Biochemistry, 30, 8171-8180].(ABSTRACT TRUNCATED AT 400 WORDS)
About this StructureAbout this Structure
1PPK is a Single protein structure of sequence from [1] with MAN, XYS, SO4, ETH and DMF as ligands. Active as Penicillopepsin, with EC number 3.4.23.20 Full crystallographic information is available from OCA.
ReferenceReference
Crystallographic analysis of transition-state mimics bound to penicillopepsin: phosphorus-containing peptide analogues., Fraser ME, Strynadka NC, Bartlett PA, Hanson JE, James MN, Biochemistry. 1992 Jun 9;31(22):5201-14. PMID:1606144
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