Structure of DNMT1

Core structure of DNMT-1

    Composed of a C terminal methyltransferase domain and an N terminal regulatory domain,linked by a conserved (Gly-Lys)n repeat.

·         The N-terminal regulatory domain contains:

1.sequence that mediate interactions of DNMT1 with other proteins;

2.a nuclear localization sequence;

3. A target recognition sequence that localizes DNMT1 to the DNA replication fork;

4. A zinc finger CXXC(CysX-X-Cys) that recognizes unmethylated CpG DNA;

5. A pair of bromo-adjacent homology(BAH) domains

·         The C-terminal methytransferase domain further folded into two subdomains:

 1.catalytic core

2.target recognition domain( TRD)

the struture overview of mDNMT-1(650-1602)
[Addapted from http://www.sciencemag.org/content/331/6020/1036.full#F1 ]

The DNA sequence

The following mechanism use complementary 12-mer DNA duplex for illustration

Complementary 12-mer Duplex[taken by http://www.sciencemag.org/content/335/6069/709.full]

The sequence shows the DNMT1 specific recognition site. The 12-mer duplex DNA is hemi-methylated, in which the Carbon-5 position of C6(methylcytosine) is methylated on the parental strand. The parental strand contains a methylcytosine at position 6(mC6), the target strand contains a 5-fluorocytosine, at position 7(fC7').