1pb3: Difference between revisions
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'''Sites of binding and orientation in a four location model for protein stereospecificity.''' | {{Structure | ||
|PDB= 1pb3 |SIZE=350|CAPTION= <scene name='initialview01'>1pb3</scene>, resolution 1.70Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene> and <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene> | |||
|ACTIVITY= [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] | |||
|GENE= ICD OR ICDA OR ICDE OR B1136 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli]) | |||
}} | |||
'''Sites of binding and orientation in a four location model for protein stereospecificity.''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1PB3 is a [ | 1PB3 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PB3 OCA]. | ||
==Reference== | ==Reference== | ||
Sites of binding and orientation in a four-location model for protein stereospecificity., Mesecar AD, Koshland DE Jr, IUBMB Life. 2000 May;49(5):457-66. PMID:[http:// | Sites of binding and orientation in a four-location model for protein stereospecificity., Mesecar AD, Koshland DE Jr, IUBMB Life. 2000 May;49(5):457-66. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/10902579 10902579] | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Isocitrate dehydrogenase (NADP(+))]] | [[Category: Isocitrate dehydrogenase (NADP(+))]] | ||
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[[Category: stereospecificity]] | [[Category: stereospecificity]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 13:22:12 2008'' | ||
Revision as of 14:22, 20 March 2008
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| , resolution 1.70Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | and | ||||||
| Gene: | ICD OR ICDA OR ICDE OR B1136 (Escherichia coli) | ||||||
| Activity: | Isocitrate dehydrogenase (NADP(+)), with EC number 1.1.1.42 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Sites of binding and orientation in a four location model for protein stereospecificity.
OverviewOverview
The stereospecificity of the enzyme isocitrate dehydrogenase was examined by steady-state kinetics and x-ray crystallography. The enzyme has the intriguing property that the apoenzyme in the absence of divalent metal showed a selectivity for the inactive l-enantiomer of the substrate isocitrate, whereas the enzyme containing magnesium showed selectivity for the physiologically active d-enantiomer. The hydrogen atom on the C2 carbon that is transferred during the reaction was, in both the d- and l-isocitrate complexes, in an orientation very close to that expected for delivery of a hydride ion to the cosubstrate NADP+. The beta-carboxylate that is eliminated as a CO2 molecule during the reaction occupied the same site on the protein in both the d- and l-isocitrate complexes. In addition, the C3 carbon was in the same protein site in both the d- and l-enantiomers. Only the fourth group, the OH atom, was in a very different position in the apo enzyme and in the metal-containing complexes. A four-location model is necessary to explain the enantiomeric specificity of IDH in contrast to the conventional three-point attachment model. The thermodynamic and kinetic ramifications of this model are explored.
About this StructureAbout this Structure
1PB3 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Sites of binding and orientation in a four-location model for protein stereospecificity., Mesecar AD, Koshland DE Jr, IUBMB Life. 2000 May;49(5):457-66. PMID:10902579
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