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1epo
From Proteopedia
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[[Image:1epo.jpg|left|200px]] | [[Image:1epo.jpg|left|200px]] | ||
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'''DIRECT OBSERVATION BY X-RAY ANALYSIS OF THE TETRAHEDRAL "INTERMEDIATE" OF ASPARTIC PROTEINASES''' | '''DIRECT OBSERVATION BY X-RAY ANALYSIS OF THE TETRAHEDRAL "INTERMEDIATE" OF ASPARTIC PROTEINASES''' | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1EPO is a [[Single protein]] structure | + | 1EPO is a [[Single protein]] structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EPO OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Cooper, J B.]] | [[Category: Cooper, J B.]] | ||
[[Category: Veerapandian, B.]] | [[Category: Veerapandian, B.]] | ||
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 15:22:56 2008'' | |
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| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 12:22, 2 May 2008
DIRECT OBSERVATION BY X-RAY ANALYSIS OF THE TETRAHEDRAL "INTERMEDIATE" OF ASPARTIC PROTEINASES
Overview
We report the X-ray analysis at 2.0 A resolution for crystals of the aspartic proteinase endothiapepsin (EC 3.4.23.6) complexed with a potent difluorostatone-containing tripeptide renin inhibitor (CP-81,282). The scissile bond surrogate, an electrophilic ketone, is hydrated in the complex. The pro-(R) (statine-like) hydroxyl of the tetrahedral carbonyl hydrate is hydrogen-bonded to both active-site aspartates 32 and 215 in the position occupied by a water in the native enzyme. The second hydroxyl oxygen of the hydrate is hydrogen-bonded only to the outer oxygen of Asp 32. These experimental data provide a basis for a model of the tetrahedral intermediate in aspartic proteinase-mediated cleavage of the amide bond. This indicates a mechanism in which Asp 32 is the proton donor and Asp 215 carboxylate polarizes a bound water for nucleophilic attack. The mechanism involves a carboxylate (Asp 32) that is stabilized by extensive hydrogen bonding, rather than an oxyanion derivative of the peptide as in serine proteinase catalysis.
About this Structure
1EPO is a Single protein structure. Full crystallographic information is available from OCA.
Reference
Direct observation by X-ray analysis of the tetrahedral "intermediate" of aspartic proteinases., Veerapandian B, Cooper JB, Sali A, Blundell TL, Rosati RL, Dominy BW, Damon DB, Hoover DJ, Protein Sci. 1992 Mar;1(3):322-8. PMID:1304340 Page seeded by OCA on Fri May 2 15:22:56 2008
