An iron-sulfur cluster in the family 4 uracil-DNA glycosylases.
The 25-kDa Family 4 uracil-DNA glycosylase (UDG) from Pyrobaculum aerophilum has been expressed and purified in large quantities for structural analysis. In the process we observed it to be colored and subsequently found that it contained iron. Here we demonstrate that P. aerophilum UDG has an iron-sulfur center with the EPR characteristics typical of a 4Fe4S high potential iron protein. Interestingly, it does not share any sequence similarity with the classic iron-sulfur proteins, although four cysteines (which are strongly conserved in the thermophilic members of Family 4 UDGs) may represent the metal coordinating residues. The conservation of these residues in other members of the family suggest that 4Fe4S clusters are a common feature. Although 4Fe4S clusters have been observed previously in Nth/MutY DNA repair enzymes, this is the first observation of such a feature in the UDG structural superfamily. Similar to the Nth/MutY enzymes, the Family 4 UDG centers probably play a structural rather than a catalytic role.
Hinks
John A
JA
Cancer Research UK DNA Repair Enzyme Group, Section of Structural Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, United Kingdom.
Evans
Michael C W
MC
De Miguel
Yolanda
Y
Sartori
Alessandro A
AA
Jiricny
Josef
J
Pearl
Laurence H
LH
D000595:Amino Acid Sequence; D002384:Catalysis; D018360:Crystallography, X-Ray; D045647:DNA Glycosylases; D004578:Electron Spin Resonance Spectroscopy; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D006358:Hot Temperature; D007501:Iron / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D016366:Open Reading Frames; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012685:Sepharose / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence; D013455:Sulfur / Q000737:chemistry*; D019624:Thermoproteaceae / Q000201:enzymology*; D014466:Ultraviolet Rays; D051981:Uracil-DNA Glycosidase
D008024:Ligands; D013455:Sulfur; D012685:Sepharose; D007501:Iron; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; D051981:Uracil-DNA Glycosidase