4ADE: Structural And Functional Study Of Succinyl-ornithine Transaminase From E. Coli

Citation:
Abstract
possesses two acyl ornithine aminotransferases, one catabolic (AstC) and the other anabolic (ArgD), that participate in L-arginine metabolism. Although only 58% identical, the enzymes have been shown to be functionally interchangeable. Here we have purified AstC and have obtained X-ray crystal structures of apo and holo-AstC and of the enzyme complexed with its physiological substrate, succinylornithine. We compare the structures obtained in this study with those of ArgD from obtained elsewhere, finding several notable differences. Docking studies were used to explore the docking modes of several substrates (ornithine, succinylornithine and acetylornithine) and the co-substrate glutamate/alpha-ketogluterate. The docking studies support our observations that AstC has a strong preference for acylated ornithine species over ornithine itself, and suggest that the increase in specificity associated with acylation is caused by steric and desolvation effects rather than specific interactions between the substrate and enzyme.
PDB ID: 4ADEDownload
MMDB ID: 106645
PDB Deposition Date: 2011/12/23
Updated in MMDB: 2013/03
Experimental Method:
x-ray diffraction
Resolution: 2.75  Å
Source Organism:
Similar Structures:
Biological Unit for 4ADE: dimeric; determined by author and by software (PISA)
Molecular Components in 4ADE
Label Count Molecule
Proteins (2 molecules)
2
Succinylornithine Transaminase(Gene symbol: astC)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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