Escherichia coli single-stranded DNA binding protein SSB promotes AlkB-mediated DNA dealkylation repair.
Biochem Biophys Res Commun
; 496(2): 274-279, 2018 02 05.
Article
in En
| MEDLINE
| ID: mdl-29326044
ABSTRACT
Repair of alkylation damage in DNA is essential for maintaining genome integrity. Escherichia coli (E.coli) protein AlkB removes various alkyl DNA adducts including N1-methyladenine (N1meA) and N3-methylcytosine (N3meC) by oxidative demethylation. Previous studies showed that AlkB preferentially removes N1meA and N3meC from single-stranded DNA (ssDNA). It can also remove N1meA and N3meC from double-stranded DNA by base-flipping. Notably, ssDNA produced during DNA replication and recombination, remains bound to E. coli single-stranded DNA binding protein SSB and it is not known whether AlkB can repair methyl adduct present in SSB-coated DNA. Here we have studied AlkB-mediated DNA repair using SSB-bound DNA as substrate. In vitro repair reaction revealed that AlkB could efficiently remove N3meC adducts inasmuch as DNA length is shorter than 20 nucleotides. However, when longer N3meC-containing oligonuleotides were used as the substrate, efficiency of AlkB catalyzed reaction was abated compared to SSB-bound DNA substrate of identical length. Truncated SSB containing only the DNA binding domain could also support the stimulation of AlkB activity, suggesting the importance of SSB-DNA interaction for AlkB function. Using 70-mer oligonucleotide containing single N3meC we demonstrate that SSB-AlkB interaction promotes faster repair of the methyl DNA adducts.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
DNA, Bacterial
/
Gene Expression Regulation, Bacterial
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Escherichia coli Proteins
/
DNA-Binding Proteins
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DNA Repair
/
Escherichia coli
/
Mixed Function Oxygenases
Language:
En
Journal:
Biochem Biophys Res Commun
Year:
2018
Type:
Article
Affiliation country:
India