DinB, the E. coli translesion synthesis polymerase, has been shown to bypass several N2-alkylguanine adducts in vitro, including N2-furfurylguanine, the structural analog of the DNA adduct formed by the antibacterial agent nitrofurazone. Recently, it was demonstrated that the Fe(II)- and α-ketoglutarate-dependent dioxygenase AlkB, a DNA repair enzyme, can dealkylate in vitro a series of N2-alky...

Natural and anthropogenic activities introduce alkanes into marine systems where they are degraded by alkane hydroxylases expressed by phylogenetically diverse bacteria. Partial sequences for alkB, one of the structural genes of alkane hydroxylase, have been used to assess the composition of alkane-degrading communities, and to determine their responses to hydrocarbon inputs. We present here th...

Alkylating agents are widespread in the environment and also occur endogenously. They can be cytotoxic or mutagenic to the cells introducing alkylated bases to DNA or RNA. All organisms have evolved multiple DNA repair mechanisms to counteract the effects of DNA alkylation: the most cytotoxic lesion, N(3)-methyladenine (3meA), is excised by AlkA glycosylase initiating base excision repair (BER)...

Cyperus rotundus L. is a perennial herb which was found prevailing in an area in the northeast of Brazil previously contaminated with petroleum. In order to enlarge the knowledge of microorganism-plant interaction in phytoremediation, the bacterial community present in the rhizosphere and roots of C. rotundus was evaluated by culture-dependent and molecular approaches. PCR-DGGE analyses based o...

The 2-oxoglutarate (2OG)- and Fe(2+)-dependent dioxygenase AlkB couples the demethylation of modified DNA to the decarboxylation of 2OG. Extensive crystallographic analyses have shown no evidence of significant structural differences between complexes binding either 2OG or succinate. By using nuclear magnetic resonance spectroscopy, we have shown that the AlkB-succinate and AlkB-2OG complexes h...

Environmental and endogenous alkylating agents generate cytotoxic and mutagenic lesions in DNA. Exposure of prokaryotic cells to sublethal doses of DNA alkylating agents induces so called adaptive response (Ada response) involving the expression of a set of genes which allows the cells to tolerate the toxic and mutagenic action of such agents. The Ada response includes the expression of four ge...

The DNA and RNA repair protein AlkB removes alkyl groups from nucleic acids by a unique ironand αketoglutarate-dependent oxidation strategy. When alkylated adenines are used as AlkB targets, earlier work suggests that the initial target of oxidation can be the alkyl carbon adjacent to N1. Such may be the case with ethano-adenine (EA), a DNA adduct formed by an important anticancer drug, BCNU, w...

The Escherichia coli AlkB protein catalyzes the direct reversal of alkylation damage to DNA; primarily 1-methyladenine (1mA) and 3-methylcytosine (3mC) lesions created by endogenous or environmental alkylating agents. AlkB is a member of the non-heme iron (II) alpha-ketoglutarate-dependent dioxygenase superfamily, which removes the alkyl group through oxidation eliminating a methyl group as for...

The Escherichia coli (E. coli) AlkB protein and its functional human homologues belong to a subfamily of 2-oxoglutarate (2OG) dependent oxygenases (2OG oxygenases for simplicity) that enable the repair of cytotoxic methylation damage in nucleic acids and that catalyze t-RNA oxidations. DNA alkylation is a major mechanism of action for cytotoxic anticancer drugs. Thus, the inhibition of oxidativ...

The Escherichia coli AlkB protein (EcAlkB) is a DNA repair enzyme which reverses methylation damage such as 1-methyladenine (1-meA) and 3-methylcytosine (3-meC). The mammalian AlkB homologues ALKBH2 and ALKBH3 display EcAlkB-like repair activity in vitro, but their substrate specificities are different, and ALKBH2 is the main DNA repair enzyme for 1-meA in vivo. The genome of the model plant Ar...