Xueqing Zou, Wen Ma, Ilia Solov'yov, Christophe Chipot, and Klaus Schulten.
Recognition of methylated DNA through methyl-CpG binding domain
proteins.
Nucleic Acids Research, 40:2747-2758, 2012.
(PMC: 3315304)
ZOU2012
DNA methylation is a key regulatory control route in epigenetics, involving gene silencing
and chromosome inactivation. It has been recognized that methyl-CpG binding domain
(MBD) proteins play an important role in interpreting the genetic information encoded by
methylated DNA (mDNA). Although the function of MBD proteins has attracted considerable
attention and is well characterized, the mechanism underlying mDNA recognition by MBD
proteins is still poorly understood. In this paper, we demonstrate that the methyl-CpG
dinucleotides are recognized at the MBD-mDNA interface by two MBD arginines through
an interplay of hydrogen bonding and cation- interaction. Through molecular
dynamics and quantum-chemistry calculations we investigate the methyl-cytosine
recognition process and demonstrate that methylation enhances MBD-mDNA binding by
increasing the hydrophobic interfacial area and by strengthening the interaction between
mDNA and MBD proteins. Free-energy perturbation calculations also show that
methylation yields favorable contribution to the binding free energy for the MBD-mDNA
complex.