1o9j: Difference between revisions
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==Overview== | ==Overview== | ||
Eta-crystallin is a retinal dehydrogenase that has acquired a role as a, structural protein in the eye lens of elephant shrews, members of an, ancient order of mammals. While it retains some activity toward retinal, which is oxidized to retinoic acid, the protein has acquired a number of, specific sequence changes that have presumably been selected to enhance, the lens role. The crystal structure of eta-crystallin, in common with, class 1 and 2 ALDHs, is a dimer of dimers. It has a better-defined NAD, binding site than those of related mammalian ALDH1 enzymes with the, cofactor bound in the "hydride transfer" position in all four monomers, with small differences about the dimer dyads. Although the active site is, well conserved, the substrate-binding site is larger in eta-crystallin, and .. | Eta-crystallin is a retinal dehydrogenase that has acquired a role as a, structural protein in the eye lens of elephant shrews, members of an, ancient order of mammals. While it retains some activity toward retinal, which is oxidized to retinoic acid, the protein has acquired a number of, specific sequence changes that have presumably been selected to enhance, the lens role. The crystal structure of eta-crystallin, in common with, class 1 and 2 ALDHs, is a dimer of dimers. It has a better-defined NAD, binding site than those of related mammalian ALDH1 enzymes with the, cofactor bound in the "hydride transfer" position in all four monomers, with small differences about the dimer dyads. Although the active site is, well conserved, the substrate-binding site is larger in eta-crystallin, and there are some mutations to the substrate access tunnel that might, affect binding or release of substrate and product. It is possible that, eta-crystallin has lost flexibility to improve its role in the lens., Enhanced binding of cofactor could enable it to act as a UV/blue light, filter in the lens, improving visual acuity. The structure not only gives, a view of a "natural mutant" of ALDH1 illustrating the adaptive conflict, that can arise in multifunctional proteins, but also provides a, well-ordered NAD binding site structure for this class of enzymes with, important roles in development and health. | ||
==About this Structure== | ==About this Structure== | ||
1O9J is a | 1O9J is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Elephantulus_edwardii Elephantulus edwardii] with NAD, DTT and DTU as [http://en.wikipedia.org/wiki/ligands ligands]. The following page contains interesting information on the relation of 1O9J with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb89_1.html Aconitase and Iron Regulatory Protein 1]]. Active as [http://en.wikipedia.org/wiki/Aldehyde_dehydrogenase_(NAD(+)) Aldehyde dehydrogenase (NAD(+))], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.2.1.3 1.2.1.3] Structure known Active Site: NDA. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1O9J OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 15:09:14 2007'' | ||
Revision as of 16:03, 5 November 2007
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THE X-RAY CRYSTAL STRUCTURE OF ETA-CRYSTALLIN
OverviewOverview
Eta-crystallin is a retinal dehydrogenase that has acquired a role as a, structural protein in the eye lens of elephant shrews, members of an, ancient order of mammals. While it retains some activity toward retinal, which is oxidized to retinoic acid, the protein has acquired a number of, specific sequence changes that have presumably been selected to enhance, the lens role. The crystal structure of eta-crystallin, in common with, class 1 and 2 ALDHs, is a dimer of dimers. It has a better-defined NAD, binding site than those of related mammalian ALDH1 enzymes with the, cofactor bound in the "hydride transfer" position in all four monomers, with small differences about the dimer dyads. Although the active site is, well conserved, the substrate-binding site is larger in eta-crystallin, and there are some mutations to the substrate access tunnel that might, affect binding or release of substrate and product. It is possible that, eta-crystallin has lost flexibility to improve its role in the lens., Enhanced binding of cofactor could enable it to act as a UV/blue light, filter in the lens, improving visual acuity. The structure not only gives, a view of a "natural mutant" of ALDH1 illustrating the adaptive conflict, that can arise in multifunctional proteins, but also provides a, well-ordered NAD binding site structure for this class of enzymes with, important roles in development and health.
About this StructureAbout this Structure
1O9J is a Single protein structure of sequence from Elephantulus edwardii with NAD, DTT and DTU as ligands. The following page contains interesting information on the relation of 1O9J with [Aconitase and Iron Regulatory Protein 1]. Active as Aldehyde dehydrogenase (NAD(+)), with EC number 1.2.1.3 Structure known Active Site: NDA. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of eta-crystallin: adaptation of a class 1 aldehyde dehydrogenase for a new role in the eye lens., Bateman OA, Purkiss AG, van Montfort R, Slingsby C, Graham C, Wistow G, Biochemistry. 2003 Apr 22;42(15):4349-56. PMID:12693930
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