1qix
From Proteopedia
(New page: 200px<br /><applet load="1qix" size="450" color="white" frame="true" align="right" spinBox="true" caption="1qix, resolution 1.9Å" /> '''PORCINE PANCREATIC EL...) |
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| - | [[Image:1qix.jpg|left|200px]]<br /><applet load="1qix" size=" | + | [[Image:1qix.jpg|left|200px]]<br /><applet load="1qix" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1qix, resolution 1.9Å" /> | caption="1qix, resolution 1.9Å" /> | ||
'''PORCINE PANCREATIC ELASTASE COMPLEXED WITH HUMAN BETA-CASOMORPHIN-7'''<br /> | '''PORCINE PANCREATIC ELASTASE COMPLEXED WITH HUMAN BETA-CASOMORPHIN-7'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Mass spectrometric screening reveals that an unmodified natural | + | Mass spectrometric screening reveals that an unmodified natural heptapeptide--human beta-casomorphin-7, an internal sequence of human beta-casein that possesses opioid-like activity--reacts with porcine pancreatic elastase to form an unusually stable acyl-enzyme complex at low pH. X-ray crystallographic analysis (to 1.9 A resolution) at pH 5 shows continuous electron density linking the C-terminal isoleucine of beta-casomorphin-7 to Ser 195 through an ester bond. The structure reveals a well defined water molecule (Wat 317), equidistant between the carbon of the ester carbonyl and N epsilon 2 of His 57. Deprotonation of Wat 317 will produce a hydroxide ion positioned to attack the ester carbonyl through the favoured Burgi-Dunitz trajectory. |
==About this Structure== | ==About this Structure== | ||
| - | 1QIX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with CA and SO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [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] Full crystallographic information is available from [http:// | + | 1QIX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [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] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QIX OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Sus scrofa]] | [[Category: Sus scrofa]] | ||
| - | [[Category: Clifton, I | + | [[Category: Clifton, I J.]] |
[[Category: Hajdu, J.]] | [[Category: Hajdu, J.]] | ||
| - | [[Category: Schofield, C | + | [[Category: Schofield, C J.]] |
| - | [[Category: Wilmouth, R | + | [[Category: Wilmouth, R C.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: SO4]] | [[Category: SO4]] | ||
[[Category: hydrolase (serine proteinase)]] | [[Category: hydrolase (serine proteinase)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:40:08 2008'' |
Revision as of 12:40, 21 February 2008
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PORCINE PANCREATIC ELASTASE COMPLEXED WITH HUMAN BETA-CASOMORPHIN-7
Overview
Mass spectrometric screening reveals that an unmodified natural heptapeptide--human beta-casomorphin-7, an internal sequence of human beta-casein that possesses opioid-like activity--reacts with porcine pancreatic elastase to form an unusually stable acyl-enzyme complex at low pH. X-ray crystallographic analysis (to 1.9 A resolution) at pH 5 shows continuous electron density linking the C-terminal isoleucine of beta-casomorphin-7 to Ser 195 through an ester bond. The structure reveals a well defined water molecule (Wat 317), equidistant between the carbon of the ester carbonyl and N epsilon 2 of His 57. Deprotonation of Wat 317 will produce a hydroxide ion positioned to attack the ester carbonyl through the favoured Burgi-Dunitz trajectory.
About this Structure
1QIX is a Single protein structure of sequence from Homo sapiens and Sus scrofa with and as ligands. Active as Pancreatic elastase, with EC number 3.4.21.36 Full crystallographic information is available from OCA.
Reference
Structure of a specific acyl-enzyme complex formed between beta-casomorphin-7 and porcine pancreatic elastase., Wilmouth RC, Clifton IJ, Robinson CV, Roach PL, Aplin RT, Westwood NJ, Hajdu J, Schofield CJ, Nat Struct Biol. 1997 Jun;4(6):456-62. PMID:9187653
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