Abstract
O6-Alkylguanine-DNA alkyltransferase (EC 2.1.1.63) repairs O6-alkylguanine lesions in DNA. A homology model of the human protein (hAT) was built, based on the crystal structure of the C-terminal domain of the Ada protein, which carries out a similar repair in Escherichia coli. Sequence alignments of known 06-alkylguanine-DNA alkyltransferases were used to aid the model building using QUANTA and CHARMm software. Despite low homology in the N-terminal half (hAT residues 1-85), a well-defined topology over this region in Ada permitted successful modelling. The C-terminal half of hAT (residues 92-207) was modelled almost entirely by residue-for-residue superposition onto the Ada structure up to residue hAT175 The model was solvated to a residue radius of 0.8 Å and then minimized using CHARMm. This structural model was used to rationalize findings from site-directed mutagenesis experiments on hAT, to make further predictions on the relationship between structure and function for the alkyltransferase family of proteins, and to explain the specificity towards known small-molecule inhibitors of the protein.
Original language | English |
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Pages (from-to) | 75-95 |
Number of pages | 21 |
Journal | Anti-Cancer Drug Design |
Volume | 10 |
Issue number | 1 |
Publication status | Published - Jan 1995 |
Keywords
- Ada protein
- alkyltransferase
- DNA repair
- homology modelling
- mutagenesis
- O-alkylguanine
- O-methylguanine