Figure 6 | Scientific Reports

Figure 6

From: Mutations in human AID differentially affect its ability to deaminate cytidine and 5-methylcytidine in ssDNA substrates in vitro

Figure 6

Interactions formed by N51 or A51 residue and methyl group or C5 atom within analyzed complexes: (a) wt hAID:AGCT, (b) wt hAID:AG5mCT, (c) N51A:AGCT, and (d) N51A:AG5mCT. The secondary structures of wt hAID and the N51A mutant are shown in gray. The selected amino acid residues that form catalytic pockets of these enzymes are indicated. The dark gray sphere represents zinc ion. The tetranucleotide substrates (AGCT or AG5mCT) docked to the catalytic pockets are shown in orange. The range of interactions of N51 or A51 residue is shown in pink. The range of interactions of the methyl group (of 5 mC) or the C5 atom (of C) is shown in green. The superposition of these two zones is shown in light blue. N51 interacts with an extensive part of the ssDNA sugar-phosphate backbone that joins C and T (within the AGCT/AG5mCT motif). A51 does not form these interactions. Specific to the methyl group are interactions with T27, W84 and an ssDNA sugar-phosphate backbone that joins C and G (within the AGCT/AG5mCT motif). In the N51A:AGCT complex, the ssDNA backbone is not anchored. Stacking interactions between W84, Y114, and G are stable only in complexes with a non-methylated substrate (wt hAID:AGCT, N51A:AGCT).

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