Figure 6.

Arg-882 involvement in DNA binding. A, methyltransferase activity of WT and R882H DNMT3A at saturating concentrations of DNA and SAM substrates after a 2-h pre-incubation with an equal amount of DNMT3L. Error bars represent S.D., n = 3. B, crystal structure of WT DNMT3A bound to DNA (PDB code 5YX2), where Arg-882 appears to be forming an interaction with the DNA phosphate backbone. C, binding affinity of WT and R882H DNMT3A for FAM-labeled dsDNA in the absence and presence of DNMT3L measured by fluorescence polarization. D, relative residence time of WT compared with R882H DNMT3A for DNA in the absence and presence of DNMT3L. 100 nm DNMT3A pre-bound to 10 nm FAM-DNA was chased with 10 μm unlabeled DNA and fluorescence polarization measured over time.