1epo
From Proteopedia
(New page: 200px<br /><applet load="1epo" size="450" color="white" frame="true" align="right" spinBox="true" caption="1epo, resolution 2.0Å" /> '''DIRECT OBSERVATION BY...) |
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| - | [[Image:1epo.jpg|left|200px]]<br /><applet load="1epo" size=" | + | [[Image:1epo.jpg|left|200px]]<br /><applet load="1epo" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1epo, resolution 2.0Å" /> | caption="1epo, resolution 2.0Å" /> | ||
'''DIRECT OBSERVATION BY X-RAY ANALYSIS OF THE TETRAHEDRAL "INTERMEDIATE" OF ASPARTIC PROTEINASES'''<br /> | '''DIRECT OBSERVATION BY X-RAY ANALYSIS OF THE TETRAHEDRAL "INTERMEDIATE" OF ASPARTIC PROTEINASES'''<br /> | ||
==Overview== | ==Overview== | ||
| - | We report the X-ray analysis at 2.0 A resolution for crystals of the | + | 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== | ==About this Structure== | ||
| - | 1EPO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ]. Active as [http://en.wikipedia.org/wiki/Endothiapepsin Endothiapepsin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.22 3.4.23.22] Full crystallographic information is available from [http:// | + | 1EPO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ]. Active as [http://en.wikipedia.org/wiki/Endothiapepsin Endothiapepsin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.23.22 3.4.23.22] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EPO OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Endothiapepsin]] | [[Category: Endothiapepsin]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Blundell, T | + | [[Category: Blundell, T L.]] |
| - | [[Category: Cooper, J | + | [[Category: Cooper, J B.]] |
[[Category: Veerapandian, B.]] | [[Category: Veerapandian, B.]] | ||
[[Category: hydrolase(acid proteinase)]] | [[Category: hydrolase(acid proteinase)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:30:16 2008'' |
Revision as of 10:30, 21 February 2008
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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 of sequence from [1]. Active as Endothiapepsin, with EC number 3.4.23.22 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
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