2ihw: Difference between revisions

Revision as of 07:31, 4 May 2008

Crystal structure of a cubic core of the dihydrolipoamide acyltransferase (E2b) component in the branched-chain alpha-ketoacid dehydrogenase complex (BCKDC), apo form

OverviewOverview

The dihydrolipoamide acyltransferase (E2b) component of the branched-chain alpha-ketoacid dehydrogenase complex forms a cubic scaffold that catalyzes acyltransfer from S-acyldihydrolipoamide to CoA to produce acyl-CoA. We have determined the first crystal structures of a mammalian (bovine) E2b core domain with and without a bound CoA or acyl-CoA. These structures reveal both hydrophobic and the previously unreported ionic interactions between two-fold-related trimers that build up the cubic core. The entrance of the dihydrolipoamide-binding site in a 30-A long active-site channel is closed in the apo and acyl-CoA-bound structures. CoA binding to one entrance of the channel promotes a conformational change in the channel, resulting in the opening of the opposite dihydrolipoamide gate. Binding experiments show that the affinity of the E2b core for dihydrolipoamide is markedly increased in the presence of CoA. The result buttresses the model that CoA binding is responsible for the opening of the dihydrolipoamide gate. We suggest that this gating mechanism synchronizes the binding of the two substrates to the active-site channel, which serves as a feed-forward switch to coordinate the E2b-catalyzed acyltransfer reaction.

About this StructureAbout this Structure

2IHW is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.

ReferenceReference

A synchronized substrate-gating mechanism revealed by cubic-core structure of the bovine branched-chain alpha-ketoacid dehydrogenase complex., Kato M, Wynn RM, Chuang JL, Brautigam CA, Custorio M, Chuang DT, EMBO J. 2006 Dec 13;25(24):5983-94. Epub 2006 Nov 23. PMID:17124494 Page seeded by OCA on Sun May 4 07:31:25 2008

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

OCA

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 [[Image:2ihw.jpg|left|200px]]
- {{Structure
+<!--
-|PDB= 2ihw |SIZE=350|CAPTION= <scene name='initialview01'>2ihw</scene>, resolution 2.700&Aring;
+The line below this paragraph, containing "STRUCTURE_2ihw", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</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/Dihydrolipoyllysine-residue_(2-methylpropanoyl)transferase Dihydrolipoyllysine-residue (2-methylpropanoyl)transferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.168 2.3.1.168] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE= DBT ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9913 Bos taurus])
+-->
-|DOMAIN=
+{{STRUCTURE_2ihw|  PDB=2ihw  |  SCENE=  }}
-|RELATEDENTRY=[[2ii3|2II3]], [[2ii4|2II4]], [[2ii5|2II5]]
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2ihw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2ihw OCA], [http://www.ebi.ac.uk/pdbsum/2ihw PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2ihw RCSB]</span>
-}}
 '''Crystal structure of a cubic core of the dihydrolipoamide acyltransferase (E2b) component in the branched-chain alpha-ketoacid dehydrogenase complex (BCKDC), apo form'''
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 A synchronized substrate-gating mechanism revealed by cubic-core structure of the bovine branched-chain alpha-ketoacid dehydrogenase complex., Kato M, Wynn RM, Chuang JL, Brautigam CA, Custorio M, Chuang DT, EMBO J. 2006 Dec 13;25(24):5983-94. Epub 2006 Nov 23. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/17124494 17124494]
 [[Category: Bos taurus]]
-[[Category: Dihydrolipoyllysine-residue (2-methylpropanoyl)transferase]]
 [[Category: Single protein]]
 [[Category: Brautigam, C A.]]
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 [[Category: Kato, M.]]
 [[Category: Wynn, R M.]]
-[[Category: apo form]]
+[[Category: Apo form]]
-[[Category: cubic core]]
+[[Category: Cubic core]]
-[[Category: homo trimer]]
+[[Category: Homo trimer]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May  4 07:31:25 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 03:44:40 2008''