Research interests Our main areas of research are in the synthesis of modified nucleosides and nucleotides and their applications. Currently we are interested in the chemical synthesis of 5'-triphosphates of base-modified, nucleoside analogues that have altered base pairing specificities. We are studying the incorporation of these analogues into DNA by polymerase enzymes in order to gain an insight into the role of base pairing during DNA replication and DNA mutagenesis. Exposure to alkylating agents can lead to the formation of highly toxic O6-alkylguanine lesions within DNA. We have developed chemical methodology for the preparation of oligodeoxyribonucleotides containing a variety of O6-alkylguanine analogues and these are being used to study DNA recognition and repair by the human protein O6-methylguanine-DNA methyltransferase (MGMT) and the alkyltransferase-like protein Atl1. Other areas of interest include the use SELEX for the design of nucleic acid-based ligands and catalysts containing chemically synthesised imidazolyl and amino modified nucleotides of dUTP and 7-deazadATP, studying the structural properties of nucleic acids containing modified pyrimidine and purine bases and the design and synthesis of modified oligodeoxyribonucleotides for DNA-DNA and DNA-protein cross-linking.