Determination of the structure of the catabolic N-succinylornithine transaminase (AstC) from Escherichia coli

Janet Newman, Shane Seabrook, Regina Surjadi, Charlotte C. Williams, Del Lucent, Matthew Wilding, Colin Scott, Thomas S. Peat

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12 Citations (Scopus)
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Abstract

Escherichia coli 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 Salmonella typhimurium 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/α-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.

Original languageEnglish
Article numbere58298
Pages (from-to)1-11
Number of pages11
JournalPLoS ONE
Volume8
Issue number3
DOIs
Publication statusPublished - 6 Mar 2013
Externally publishedYes

Bibliographical note

Copyright the Author(s) 2013. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

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    Newman, J., Seabrook, S., Surjadi, R., Williams, C. C., Lucent, D., Wilding, M., ... Peat, T. S. (2013). Determination of the structure of the catabolic N-succinylornithine transaminase (AstC) from Escherichia coli. PLoS ONE, 8(3), 1-11. [e58298]. https://doi.org/10.1371/journal.pone.0058298