1ika: Difference between revisions

Revision as of 20:05, 2 May 2008

STRUCTURE OF ISOCITRATE DEHYDROGENASE WITH ALPHA-KETOGLUTARATE AT 2.7 ANGSTROMS RESOLUTION: CONFORMATIONAL CHANGES INDUCED BY DECARBOXYLATION OF ISOCITRATE

OverviewOverview

The structure of the isocitrate dehydrogenase (IDH) complex with bound alpha-ketoglutarate, Ca2+, and NADPH was solved at 2.7-A resolution. The alpha-ketoglutarate binds in the active site at the same position and orientation as isocitrate, with a difference between the two bound molecules of about 0.8 A. The Ca2+ metal is coordinated by alpha-ketoglutarate, three conserved aspartate residues, and a pair of water molecules. The largest motion in the active site relative to the isocitrate enzyme complex is observed for tyrosine 160, which originally forms a hydrogen bond to the labile carboxyl group of isocitrate and moves to form a new hydrogen bond to Asp 307 in the complex with alpha-ketoglutarate. This triggers a number of significant movements among several short loops and adjoining secondary structural elements in the enzyme, most of which participate in dimer stabilization and formation of the active-site cleft. These rearrangements are similar to the ligand-binding-induced movements observed in globins and insulin and serve as a model for an enzymatic mechanism which involves local shifts of secondary structural elements during turnover, rather than large-scale domain closures or loop transitions induced by substrate binding such as those observed in hexokinase or triosephosphate isomerase.

About this StructureAbout this Structure

1IKA is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.

ReferenceReference

Structure of isocitrate dehydrogenase with alpha-ketoglutarate at 2.7-A resolution: conformational changes induced by decarboxylation of isocitrate., Stoddard BL, Koshland DE Jr, Biochemistry. 1993 Sep 14;32(36):9317-22. PMID:8369301 Page seeded by OCA on Fri May 2 20:05:43 2008

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OCA

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 [[Image:1ika.gif|left|200px]]
- {{Structure
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-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Isocitrate_dehydrogenase_(NADP(+)) Isocitrate dehydrogenase (NADP(+))], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.42 1.1.1.42] </span>
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-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1ika FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ika OCA], [http://www.ebi.ac.uk/pdbsum/1ika PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1ika RCSB]</span>
-}}
 '''STRUCTURE OF ISOCITRATE DEHYDROGENASE WITH ALPHA-KETOGLUTARATE AT 2.7 ANGSTROMS RESOLUTION: CONFORMATIONAL CHANGES INDUCED BY DECARBOXYLATION OF ISOCITRATE'''
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 Structure of isocitrate dehydrogenase with alpha-ketoglutarate at 2.7-A resolution: conformational changes induced by decarboxylation of isocitrate., Stoddard BL, Koshland DE Jr, Biochemistry. 1993 Sep 14;32(36):9317-22. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/8369301 8369301]
 [[Category: Escherichia coli]]
-[[Category: Isocitrate dehydrogenase (NADP(+))]]
 [[Category: Single protein]]
 [[Category: Junior, D E.Koshland.]]
 [[Category: Stoddard, B L.]]
-[[Category: oxidoreductase(nad(a)-choh(d))]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 20:05:43 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 21:21:01 2008''