2BE9:
reference: Crystal structure of Sulfolobus acidocaldarius aspartate carbamoyltransferase in complex with its allosteric activator CTP., De Vos D, Xu Y, Aerts T, Van Petegem F, Van Beeumen JJ, Biochem Biophys Res Commun. 2008 Jul 18;372(1):40-4. Epub 2008 May 12. PMID: 18477471

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