3dc1

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3dc1, resolution 2.50Å ()
Ligands: ,
Non-Standard Residues:
Gene: AADAT, KAT2 (Homo sapiens)
Resources: FirstGlance, OCA, RCSB, PDBsum
Coordinates: save as pdb, mmCIF, xml



Crystal structure of kynurenine aminotransferase II complex with alpha-ketoglutarate

Publication Abstract from PubMed

KAT (kynurenine aminotransferase) II is a primary enzyme in the brain for catalysing the transamination of kynurenine to KYNA (kynurenic acid). KYNA is the only known endogenous antagonist of the N-methyl-D-aspartate receptor. The enzyme also catalyses the transamination of aminoadipate to alpha-oxoadipate; therefore it was initially named AADAT (aminoadipate aminotransferase). As an endotoxin, aminoadipate influences various elements of glutamatergic neurotransmission and kills primary astrocytes in the brain. A number of studies dealing with the biochemical and functional characteristics of this enzyme exist in the literature, but a systematic assessment of KAT II addressing its substrate profile and kinetic properties has not been performed. The present study examines the biochemical and structural characterization of a human KAT II/AADAT. Substrate screening of human KAT II revealed that the enzyme has a very broad substrate specificity, is capable of catalysing the transamination of 16 out of 24 tested amino acids and could utilize all 16 tested alpha-oxo acids as amino-group acceptors. Kinetic analysis of human KAT II demonstrated its catalytic efficiency for individual amino-group donors and acceptors, providing information as to its preferred substrate affinity. Structural analysis of the human KAT II complex with alpha-oxoglutaric acid revealed a conformational change of an N-terminal fraction, residues 15-33, that is able to adapt to different substrate sizes, which provides a structural basis for its broad substrate specificity.

Substrate specificity and structure of human aminoadipate aminotransferase/kynurenine aminotransferase II., Han Q, Cai T, Tagle DA, Robinson H, Li J, Biosci Rep. 2008 Aug;28(4):205-15. PMID:18620547

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

About this Structure

3dc1 is a 4 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

  • Han Q, Cai T, Tagle DA, Robinson H, Li J. Substrate specificity and structure of human aminoadipate aminotransferase/kynurenine aminotransferase II. Biosci Rep. 2008 Aug;28(4):205-15. PMID:18620547 doi:10.1042/BSR20080085

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