Interaction of Escherichia coli Formamidopyrimidine-DNA Glycosylase (Fpg) with Damaged DNA Containing an 7,8-Dihydro-8-oxoguanine Lesion.
EMSL Project ID
4098
Abstract
7,8-Dihydro-8-oxoguanine (8OG) is a stable product of oxidative DNA damage, and is a substrate for base excision repair (BER) by DNA glycosylases that recognize and remove the damaged base. In prokaryotes the BER enzyme is formamidopyrimdine-DNA glycosylase (FPG), a protein that removes 8OG and other oxidized bases from the genome. In vitro, unrepaired 8OG is bypassed by DNA polymerases, coding for a nonmutagenic C and to a lesser extent a mutagenic A. In the past years crystal structures of free FPG and FPG either covalently bound to DNA or complexed with abasic site analogue-containing DNA have been solved (Sugahara et al., 2000; Fromme & Verdine, 2002; Serre et al., 2002). The structures have provided a valuable picture of how the 8OG-containing DNA is remodeled in preparation for glycosylase activity and a detailed understanding of the biochemical nature of the enzymatic steps. However, none of the structures provide insight into the thermodynamic events that occur starting from when FPG ?recognizes? the 8OG lesion in the vast background of undamaged DNA and ending when the remodeled structure is assembled in a bound complex. Furthermore, no explanation has been forthcoming as to why the 8OG cleavage efficiency depends on sequence context. To address these problems we plan to study the structure, dynamics and thermodynamics of 8OG containing DNA and to study the dynamics at the active site of Fpg (Buchko et al., 2001).
Project Details
Project type
Capability Research
Start Date
2003-10-01
End Date
2006-10-08
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
G.W. Buchko, N.J. Hess, V. Bandaru, S.S. Wallace, and M.A. Kennedy. (2000) Spectroscopic studies of zinc (II) and cobalt (II) associated Escherichia coli formamidopyrimidine-DNA glycosylase: Extended X-ray absorption fine structure evidence for a metal binding domain. Biochemistry 39:12441-12449.