title: Conserved threonine 1505 in the catalytic domain stabilizes mouse DNA methyltransferase 1.
abstract: In mammals, DNA methyltransferase 1 (DNMT1) is responsible for propagating the DNA methylation pattern into the next generation through selective methylation of hemi-methylated CpG that emerges just after replication, a process known as maintenance methylation. The T1505, which is conserved among DNMT1s of vertebrates, in the catalytic domain of mouse DNMT1 forms the hydrogen bond with the W1512, which is also conserved among vertebrates and one of the essential residues in recognition of the 5-methylcytosine in hemi-methylated CpGs. However, importance of the hydrogen bond between T1505 and W1512 is unknown. In this study, we determined the crystal structure of mouse DNMT1(291-1620) that replaced T1505 with alanine (DNMT1(291-1620)T1505A) and examined its DNA methylation activity in vitro. Although the mutation lost the hydrogen bond between T1505 and W1512, the overall structure of DNMT1(291-1620)T1505A remained almost identical with that of the wild type. Structural stability and DNA methylation activity of DNMT1(291-1620)T1505A under physiological temperature were lower than those of DNMT1(291-1620). T1505 is crucial on the DNA methylation activity of DNMT1 through stabilizing its structure during ongoing round of DNA methylation.
authors.affiliation: The Laboratory of Supramolecular Crystallography, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Kensaku
authors.initials: K
authors.lastname: Kanada
authors.affiliation: The Laboratory of Supramolecular Crystallography, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Takeshita
authors.affiliation: The Laboratory of Epigenetics, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Suetake
authors.affiliation: The Laboratory of Epigenetics, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Tajima
authors.affiliation: The Laboratory of Supramolecular Crystallography, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakagawa
mesh_terms: D000818:Animals; D055162:Biocatalysis; D020134:Catalytic Domain; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000737:chemistry* / Q000378:metabolism*; D004795:Enzyme Stability; D051379:Mice; D013912:Threonine / Q000378:metabolism*
chemical_list: D013912:Threonine; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619381:Dnmt1 protein, mouse
keywords: DNA methyltransferase; X-ray crystallography; epigenetics; hemi-methylated DNA; maintenance methylation