8est
From Proteopedia
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|PDB= 8est |SIZE=350|CAPTION= <scene name='initialview01'>8est</scene>, resolution 1.78Å | |PDB= 8est |SIZE=350|CAPTION= <scene name='initialview01'>8est</scene>, resolution 1.78Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= | + | |LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=GIS:ETHYL-(2-CARBOXY-4-GUANIDINIUM-PHENYL)-CHLOROACETATE'>GIS</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene> |
| - | |ACTIVITY= [http://en.wikipedia.org/wiki/Pancreatic_elastase Pancreatic elastase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.36 3.4.21.36] | + | |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Pancreatic_elastase Pancreatic elastase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.36 3.4.21.36] </span> |
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY= | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=8est FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8est OCA], [http://www.ebi.ac.uk/pdbsum/8est PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=8est RCSB]</span> | ||
}} | }} | ||
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[[Category: Powers, J C.]] | [[Category: Powers, J C.]] | ||
[[Category: Radhakrishnan, R.]] | [[Category: Radhakrishnan, R.]] | ||
| - | [[Category: CA]] | ||
| - | [[Category: GIS]] | ||
| - | [[Category: SO4]] | ||
[[Category: hydrolase(serine proteinase)]] | [[Category: hydrolase(serine proteinase)]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 05:45:09 2008'' |
Revision as of 02:45, 31 March 2008
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| , resolution 1.78Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , | ||||||
| Activity: | Pancreatic elastase, with EC number 3.4.21.36 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
REACTION OF PORCINE PANCREATIC ELASTASE WITH 7-SUBSTITUTED 3-ALKOXY-4-CHLOROISOCOUMARINS: DESIGN OF POTENT INHIBITORS USING THE CRYSTAL STRUCTURE OF THE COMPLEX FORMED WITH 4-CHLORO-3-ETHOXY-7-GUANIDINO-ISOCOUMARIN
Overview
The crystal structure of the acyl enzyme formed upon inhibition of porcine pancreatic elastase (PPE) by 4-chloro-3-ethoxy-7-guanidinoisocoumarin has been determined at a 1.85-A effective resolution. The chlorine atom is still present in this acyl enzyme, in contrast to the previously reported structure of the 7-amino-4-chloro-3-methoxyisocoumarin-PPE complex where the chlorine atom has been replaced by an acetoxy group. The guanidino group forms hydrogen bonds with the carbonyl group and side-chain hydroxyl group of Thr-41, and the acyl carbonyl group has been twisted out of the oxyanion hole. Molecular modeling indicates that the orientation of the initial Michaelis enzyme-inhibitor complex is quite different from that of the acyl enzyme since simple reconstruction of the isocoumarin ring would result in unfavorable interactions with Ser-195 and His-57. Molecular models were used to design a series of new 7-(alkylureido)- and 7-(alkylthioureido)-substituted derivatives of 3-alkoxy-7-amino-4-chloroisocoumarin as PPE inhibitors. All the 3-ethoxyisocoumarins were better inhibitors than those in the 3-methoxy series due to better interactions with the S1 pocket of PPE. The best ureido inhibitor also contained a tert-butylureido group at the 7-position of the isocoumarin. Due to a predicted interaction with a small hydrophobic pocket on the surface of PPE, this isocoumarin and a related phenylthioureido derivative are among the best irreversible inhibitors thus far reported for PPE (kobs/[I] = 8100 M-1 s-1 and 12,000 M-1 s-1). Kinetic studies of the stability of enzyme-inhibitor complexes suggest that many isocoumarins are alkylating the active site histidine at pH 7.5 via a quinone imine methide intermediate, while at pH 5.0, the predominant pathway appears to be simple formation of a stable acyl enzyme derivative.
About this Structure
8EST is a Single protein structure of sequence from Sus scrofa. Full crystallographic information is available from OCA.
Reference
Reaction of porcine pancreatic elastase with 7-substituted 3-alkoxy-4-chloroisocoumarins: design of potent inhibitors using the crystal structure of the complex formed with 4-chloro-3-ethoxy-7-guanidinoisocoumarin., Powers JC, Oleksyszyn J, Narasimhan SL, Kam CM, Biochemistry. 1990 Mar 27;29(12):3108-18. PMID:2337582
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