2bb4: Difference between revisions

Revision as of 20:03, 3 May 2008

Porcine pancreatic elastase complexed with beta-casomorphin-7 and Asp-Phe at pH 5.0

OverviewOverview

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 StructureAbout this Structure

2BB4 is a Single protein structure of sequence from Sus scrofa. Full crystallographic information is available from OCA.

ReferenceReference

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 Page seeded by OCA on Sat May 3 20:03:41 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

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 [[Image:2bb4.gif|left|200px]]
- {{Structure
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+The line below this paragraph, containing "STRUCTURE_2bb4", creates the "Structure Box" on the page.
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+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=ASP:ASPARTIC+ACID'>ASP</scene>, <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=PHE:PHENYLALANINE'>PHE</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|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>
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-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2bb4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2bb4 OCA], [http://www.ebi.ac.uk/pdbsum/2bb4 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2bb4 RCSB]</span>
-}}
 '''Porcine pancreatic elastase complexed with beta-casomorphin-7 and Asp-Phe at pH 5.0'''
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 [[Category: Schofield, C J.]]
 [[Category: Wilmouth, R C.]]
-[[Category: serine proteinase]]
+[[Category: Serine proteinase]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 20:03:41 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 02:03:45 2008''