title: Thermostable uracil-DNA glycosylase from Thermotoga maritima a member of a novel class of DNA repair enzymes.
abstract: Uracil-DNA glycosylase (UDG) is a ubiquitous enzyme found in eukaryotes and prokaryotes [1][2][3]. This enzyme removes uracil bases that are present in DNA as a result of either deamination of cytosine or misincorporation of dUMP instead of dTMP [4] [5], and it is the primary activity in the DNA base excision repair pathway. Although UDG activities have been shown to be present in several thermophiles [6][7][8], no sequences have been found that are complementary to the Escherichia coli ung gene, which encodes UDG [9]. Here, we describe a UDG from the thermophile Thermotoga maritima. The T. maritima UDG gene has a low level of homology to the E. coli G-T/U mismatch-specific DNA glycosylase gene (mug). The expressed protein is capable of removing uracil from DNA containing either a U-A or a U-G base pair and is heat-stable up to 75 degrees C. The enzyme is also active on single-stranded DNA containing uracil. Analogous genes appear to be present in several prokaryotic organisms, including thermophilic and mesophilic eubacteria as well as archaebacteria, the human-disease pathogens Treponema palladium and Rickettsia prowazekii, and the extremely radioresistant organism Deinococcus radiodurans. These findings suggest that the T. maritima UDG is a member of a new class of DNA repair enzymes.
authors.affiliation: Departments of Radiology and Radiation Oncology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA.
authors.forename: M
authors.initials: M
authors.lastname: Sandigursky
authors.forename: W A
authors.initials: WA
authors.lastname: Franklin
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D005075:Biological Evolution; D003001:Cloning, Molecular; D045647:DNA Glycosylases; D017931:DNA Primers; D004260:DNA Repair; D004795:Enzyme Stability; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D020124:Thermotoga maritima / Q000201:enzymology*; D051981:Uracil-DNA Glycosidase
chemical_list: D017931:DNA Primers; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; D051981:Uracil-DNA Glycosidase