1ai2
From Proteopedia
(New page: 200px<br /><applet load="1ai2" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ai2, resolution 1.9Å" /> '''ISOCITRATE DEHYDROGEN...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1ai2.gif|left|200px]]<br /><applet load="1ai2" size=" | + | [[Image:1ai2.gif|left|200px]]<br /><applet load="1ai2" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1ai2, resolution 1.9Å" /> | caption="1ai2, resolution 1.9Å" /> | ||
'''ISOCITRATE DEHYDROGENASE COMPLEXED WITH ISOCITRATE, NADP+, AND CALCIUM (FLASH-COOLED)'''<br /> | '''ISOCITRATE DEHYDROGENASE COMPLEXED WITH ISOCITRATE, NADP+, AND CALCIUM (FLASH-COOLED)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Small structural perturbations in the enzyme isocitrate dehydrogenase | + | Small structural perturbations in the enzyme isocitrate dehydrogenase (IDH) were made in order to evaluate the contribution of precise substrate alignment to the catalytic power of an enzyme. The reaction trajectory of IDH was modified (i) after the adenine moiety of nicotinamide adenine dinucleotide phosphate was changed to hypoxanthine (the 6-amino was changed to 6-hydroxyl), and (ii) by replacing Mg2+, which has six coordinating ligands, with Ca2+, which has eight coordinating ligands. Both changes make large (10(-3) to 10(-5)) changes in the reaction velocity but only small changes in the orientation of the substrates (both distance and angle) as revealed by cryocrystallographic trapping of active IDH complexes. The results provide evidence that orbital overlap produced by optimal orientation of reacting orbitals plays a major quantitative role in the catalytic power of enzymes. |
==About this Structure== | ==About this Structure== | ||
| - | 1AI2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with NAP and ICA as [http://en.wikipedia.org/wiki/ligands ligands]. This structure | + | 1AI2 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=NAP:'>NAP</scene> and <scene name='pdbligand=ICA:'>ICA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. This structure supersedes the now removed PDB entry 1IKB. Active as [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] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AI2 OCA]. |
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Isocitrate dehydrogenase (NADP(+))]] | [[Category: Isocitrate dehydrogenase (NADP(+))]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Junior, D | + | [[Category: Junior, D E.Koshland.]] |
[[Category: Mesecar, A.]] | [[Category: Mesecar, A.]] | ||
| - | [[Category: Stoddard, B | + | [[Category: Stoddard, B L.]] |
[[Category: ICA]] | [[Category: ICA]] | ||
[[Category: NAP]] | [[Category: NAP]] | ||
| Line 24: | Line 24: | ||
[[Category: phosphorylation]] | [[Category: phosphorylation]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:44:43 2008'' |
Revision as of 09:44, 21 February 2008
|
ISOCITRATE DEHYDROGENASE COMPLEXED WITH ISOCITRATE, NADP+, AND CALCIUM (FLASH-COOLED)
Overview
Small structural perturbations in the enzyme isocitrate dehydrogenase (IDH) were made in order to evaluate the contribution of precise substrate alignment to the catalytic power of an enzyme. The reaction trajectory of IDH was modified (i) after the adenine moiety of nicotinamide adenine dinucleotide phosphate was changed to hypoxanthine (the 6-amino was changed to 6-hydroxyl), and (ii) by replacing Mg2+, which has six coordinating ligands, with Ca2+, which has eight coordinating ligands. Both changes make large (10(-3) to 10(-5)) changes in the reaction velocity but only small changes in the orientation of the substrates (both distance and angle) as revealed by cryocrystallographic trapping of active IDH complexes. The results provide evidence that orbital overlap produced by optimal orientation of reacting orbitals plays a major quantitative role in the catalytic power of enzymes.
About this Structure
1AI2 is a Single protein structure of sequence from Escherichia coli with and as ligands. This structure supersedes the now removed PDB entry 1IKB. Active as Isocitrate dehydrogenase (NADP(+)), with EC number 1.1.1.42 Full crystallographic information is available from OCA.
Reference
Orbital steering in the catalytic power of enzymes: small structural changes with large catalytic consequences., Mesecar AD, Stoddard BL, Koshland DE Jr, Science. 1997 Jul 11;277(5323):202-6. PMID:9211842
Page seeded by OCA on Thu Feb 21 11:44:43 2008
