1af2
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CRYSTAL STRUCTURE OF CYTIDINE DEAMINASE COMPLEXED WITH URIDINE
OverviewOverview
Crystal structures of the cytidine deaminase-uridine product complex, prepared either by cocrystallizing enzyme with uridine or by diffusing, cytidine into ligand-free crystals show that the product binds as a, 4-ketopyrimidine. They reveal four additional features of the catalytic, process. (1) A water molecule bound to a site previously observed to bind, the incoming 4-NH2 group represents the site for the leaving ammonia, molecule. The conserved Pro 128 accommodates both moieties by orienting, the carbonyl group of the previous residue. (2) The Glu 104 carboxylate, group rotates from its hydrogen bond to the O4 hydroxyl group in, transition-state analog complexes, forming a new hydrogen bond to the, leaving group moiety. Thus, after stabilizing the hydroxyl group in the, transition ... [(full description)]
About this StructureAbout this Structure
1AF2 is a [Single protein] structure of sequence from [Escherichia coli] with ZN and U as [ligands]. Active as [[1]], with EC number [3.5.4.5]. Full crystallographic information is available from [OCA].
ReferenceReference
The structure of the cytidine deaminase-product complex provides evidence for efficient proton transfer and ground-state destabilization., Xiang S, Short SA, Wolfenden R, Carter CW Jr, Biochemistry. 1997 Apr 22;36(16):4768-74. PMID:9125497
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