1akz
HUMAN URACIL-DNA GLYCOSYLASE
OverviewOverview
Crystal structures of the DNA repair enzyme human uracil-DNA glycosylase (UDG), combined with mutational analysis, reveal the structural basis for the specificity of the enzyme. Within the classic alpha/beta fold of UDG, sequence-conserved residues form a positively charged, active-site groove the width of duplex DNA, at the C-terminal edge of the central four-stranded parallel beta sheet. In the UDG-6-aminouracil complex, uracil binds at the base of the groove within a rigid preformed pocket that confers selectivity for uracil over other bases by shape complementary and by main chain and Asn-204 side chain hydrogen bonds. Main chain nitrogen atoms are positioned to stabilize the oxyanion intermediate generated by His-268 acting via nucleophilic attack or general base mechanisms. Specific binding of uracil flipped out from a DNA duplex provides a structural mechanism for damaged base recognition.
About this StructureAbout this Structure
1AKZ is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure and mutational analysis of human uracil-DNA glycosylase: structural basis for specificity and catalysis., Mol CD, Arvai AS, Slupphaug G, Kavli B, Alseth I, Krokan HE, Tainer JA, Cell. 1995 Mar 24;80(6):869-78. PMID:7697717 Page seeded by OCA on Fri May 2 10:24:23 2008