Nucleoside-Driven Specificity of DNA Methyltransferase** |
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Authors: | Dr. Madhuri Gade Dr. Jasmine M. Gardner Dr. Prashant Jain Prof. Paola Laurino |
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Affiliation: | 1. Protein Engineering and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495 Japan;2. Department of Chemistry – BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden |
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Abstract: | We have studied the adenosine binding specificities of two bacterial DNA methyltransferases, Taq methyltransferase (M.TaqI), and HhaI methyltransferase (M.HhaI). While they have similar cofactor binding pocket interactions, experimental data showed different specificity for novel S-nucleobase-l -methionine cofactors (SNMs; N=guanosyl, cytidyl, uridyl). Protein dynamics corroborate the experimental data on the cofactor specificities. For M.TaqI the specificity for S-adenosyl-l -methionine (SAM) is governed by the tight binding on the nucleoside part of the cofactor, while for M.HhaI the degree of freedom of the nucleoside chain allows the acceptance of other bases. The experimental data prove catalytically productive methylation by the M.HhaI binding pocket for all the SNMs. Our results suggest a new route for successful design of unnatural SNM analogues for methyltransferases as a tool for cofactor engineering. |
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Keywords: | DNA methylation enzyme dynamics methyltransferases nucleobases |
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