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3dc1
From Proteopedia
| 3dc1, resolution 2.50Å () | |||||||||
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| Sites: | , , , , and | ||||||||
| Ligands: | , | ||||||||
| Non-Standard Residues: | |||||||||
| Gene: | AADAT, KAT2 (Homo sapiens) | ||||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
Crystal structure of kynurenine aminotransferase II complex with alpha-ketoglutarate
Kynurenine aminotransferase II (KAT-II) is a primary enzyme in the brain for catalyzing the transamination of kynurenine to kynurenic acid (KYNA). KYNA is the only known endogenous antagonist of N-methyl-D-aspartate receptor. The enzyme also catalyzes the transamination of aminoadipate to alpha-ketoadipate; therefore it was initially named aminoadipate aminotransferase (AADAT). Aminoadipate, as an excitotoxin, 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 in regards its substrate profile and kinetic properties has not been addressed. This study concerns the biochemical and structural characterization of a human KAT II/AADAT. Substrate screening of human KAT II revealed that the enzyme had very broad substrate specificity, was capable of catalyzing the transamination of 16 out of 24 tested amino acids and utilized all 16 tested alpha-keto 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 human KAT II complex with alpha-ketoglutaric acid revealed a conformation change of an N-terminal fraction, residues 15-33, that is able to adapt 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 Jul 14. PMID:18620547
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
About this Structure
3DC1 is a 4 chains structure of sequences 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
Page seeded by OCA on Mon Feb 16 11:07:12 2009
