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Single‐Stranded Oligodeoxyribonucleotides Are Substrates of Fpg Protein from Escherichia Coli
Author(s) -
Ishchenko Alexander A.,
Bulychev Nikolai V.,
Maksakova Galia A.,
Johnson Francis,
Nevinsky Georgy A.
Publication year - 1999
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/713803570
Subject(s) - escherichia coli , chemistry , dna , biochemistry , dna glycosylase , purine , enzyme , microbiology and biotechnology , stereochemistry , biology , dna damage , gene
The interaction of Escherichia coli Fpg protein, which catalyzes excision of several damaged purine bases including 8‐oxoguanine (oxoG) from DNA with a set of single‐ (ss) and double‐stranded (ds) 23‐mer oligodeoxyribonucleotides (ODNs) containing 8‐oxoguanine(s) at various positions, has been investigated. The affinities of different ss ODNs (KM = 0.55‐1.3 muM) were shown to be 12‐170 times less than those for corresponding ds ODNs (KM = 6‐60 nM). Depending on the position of the oxoG within the ODNs, relative initial rates of conversion of ss substrates may be less than, comparable, or greater than those for ds ODNs. The enzyme can remove 5′‐terminal oxoG from ODNs only if the 5′‐end is phosphorylated. Fpg does not release oxoG residues from the ultimate and penultimate 3′‐terminal positions. Duplexes containing two adjacent oxoG are poor substrates for the glycosylase.