View source for 2b04

[[Image:2b04.gif|left|200px]]<br /><applet load="2b04" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="2b04, resolution 2.50&Aring;" />
'''Crystal Structure of Porcine Pancreatic Phospholipase A2 in Complex with Glycochenodeoxycholate'''<br />

==Overview==
Bile salt interactions with phospholipid monolayers of fat emulsions are, known to regulate the actions of gastrointestinal lipolytic enzymes in, order to control the uptake of dietary fat. Specifically, on the, lipid/aqueous interface of fat emulsions, the anionic portions of, amphipathic bile salts have been thought to interact with and activate the, enzyme group-IB phospholipase A2 (PLA2) derived from the pancreas. To, explore this regulatory process, we have determined the crystal structures, of the complexes of pancreatic PLA2 with the naturally occurring bile, salts: cholate, glycocholate, taurocholate, glycochenodeoxycholate, and, taurochenodeoxycholate. The five PLA2-bile salt complexes each result in a, partly occluded active site, and the resulting ligand binding displays, specific hydrogen bonding interactions and extensive hydrophobic packing., The amphipathic bile salts are bound to PLA2 with their polar hydroxyl and, sulfate/carboxy groups oriented away from the enzyme's hydrophobic core., The impaired catalytic and interface binding functions implied by these, structures provide a basis for the previous numerous observations of a, biphasic dependence of the rate of PLA2 catalyzed hydrolysis of, zwitterionic glycerophospholipids in the presence of bile salts. The, rising or activation phase is consistent with enhanced binding and, activation of the bound PLA2 by the bile salt induced anionic charge in a, zwitterionic interface. The falling or inhibitory phase can be explained, by the formation of a catalytically inert stoichiometric complex between, PLA2 and any bile salts in which it forms a stable complex. The model, provides new insight into the regulatory role that specific PLA2-bile salt, interactions are likely to play in fat metabolism.

==About this Structure==
2B04 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with <scene name='pdbligand=CHO:'>CHO</scene>, <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=CL:'>CL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Phospholipase_A(2) Phospholipase A(2)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.1.4 3.1.1.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2B04 OCA]. 

==Reference==
Structural basis for bile salt inhibition of pancreatic phospholipase A2., Pan YH, Bahnson BJ, J Mol Biol. 2007 Jun 1;369(2):439-50. Epub 2007 Mar 20. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17434532 17434532]
[[Category: Phospholipase A(2)]]
[[Category: Single protein]]
[[Category: Sus scrofa]]
[[Category: Bahnson, B.J.]]
[[Category: Jain, M.K.]]
[[Category: Pan, Y.H.]]
[[Category: CA]]
[[Category: CHO]]
[[Category: CL]]
[[Category: bile salt]]
[[Category: binding]]
[[Category: carboxylic ester hydrolase]]
[[Category: glycochenodeoxycholate]]
[[Category: pancreatic enzyme]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 15:08:52 2008''