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Characterisation of Archaeglobus fulgidus AlkA hypoxanthine DNA glycosylase activity
Author(s) -
Mansfield Colin,
Kerins Sinéad M,
McCarthy Tommie V
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)00257-6
Subject(s) - dna glycosylase , hypoxanthine , chemistry , biochemistry , dna , uracil dna glycosylase , dna repair , enzyme
The AlkA protein from the archaebacterium Archaeglobus fulgidus was characterised with respect to release of hypoxanthine from DNA. The hypoxanthine glycosylase activity had optimal activity at 60°C at pH 5.0. The enzyme released hypoxanthine from substrates with a preference for dI:dG≫dI:dT>dI:dC>dI:dA. The presence of a mismatch on either side of the dIMP in the substrate reduced excision efficiency of the hypoxanthine residue at neutral pH, while a mismatch on both sides of the dIMP resulted in total loss of excision. Release of hypoxanthine from DNA required a minimum of two bases on the 5′ side and four bases on the 3′ side of the dIMP residue.