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A/T Run Geometry of B-form DNA Is Independent of Bound Methyl-CpG Binding Domain, Cytosine Methylation and Flanking Sequence

DOI: 10.1038/srep31210 DOI Help

Authors: Jyh Yea Chia (1Department of Pathology, Faculty of Medicine and Health Sciences; Universiti Putra Malaysia) , Wen Siang Tan (Universiti Putra Malaysia) , Chyan Leong Ng (Institute of Systems Biology, Universiti Kebangsaan Malaysia) , Nien-jen Hu (5Institute of Biochemistry, National Chung Hsing University) , Hooi Ling Foo (Universiti Putra Malaysia) , Kok Lian Ho (Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia (UPM))
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Scientific Reports , VOL 6

State: Published (Approved)
Published: August 2016
Diamond Proposal Number(s): 4927

Open Access Open Access

Abstract: DNA methylation in a CpG context can be recognised by methyl-CpG binding protein 2 (MeCP2) via its methyl-CpG binding domain (MBD). An A/T run next to a methyl-CpG maximises the binding of MeCP2 to the methylated DNA. The A/T run characteristics are reported here with an X-ray structure of MBD A140V in complex with methylated DNA. The A/T run geometry was found to be strongly stabilised by a string of conserved water molecules regardless of its flanking nucleotide sequences, DNA methylation and bound MBD. New water molecules were found to stabilise the Rett syndrome-related E137, whose carboxylate group is salt bridged to R133. A structural comparison showed no difference between the wild type and MBD A140V. However, differential scanning calorimetry showed that the melting temperature of A140V constructs in complex with methylated DNA was reduced by ~7 °C, although circular dichroism showed no changes in the secondary structure content for A140V. A band shift analysis demonstrated that the larger fragment of MeCP2 (A140V) containing the transcriptional repression domain (TRD) destabilises the DNA binding. These results suggest that the solution structure of MBD A140V may differ from the wild-type MBD although no changes in the biochemical properties of X-ray A140V were observed.

Subject Areas: Chemistry, Biology and Bio-materials

Instruments: I02-Macromolecular Crystallography