Active Site

DNA methylase, C-5 cytosine-specific, active site (IPR018117)

Short name: C5_DNA_meth_AS

Description

C-5 cytosine-specific DNA methylases (C5 Mtase) are enzymes that specifically methylate the C-5 carbon of cytosines in DNA [PMID: 3248729, PMID: 8127644, PMID: 2716049]. Such enzymes are found in the proteins described below.

  • As a component of type II restriction-modification systems in prokaryotes and some bacteriophages. Such enzymes recognise a specific DNA sequence where they methylate a cytosine. In doing so, they protect DNA from cleavage by type II restriction enzymes that recognise the same sequence. The sequences of a large number of type II C-5 Mtases are known.
  • In vertebrates, there are a number of C-5 Mtases that methylate CpG dinucleotides. The sequence of the mammalian enzyme is known.

C-5 Mtases share a number of short conserved regions. One of the conserved regions contains a conserved Pro-Cys dipeptide in which the cysteine has been shown [PMID: 1932026] to be involved in the catalytic mechanism; it appears to form a covalent intermediate with the C6 position of cytosine. The second smaller region is located at the C-terminal extremity in type-II enzymes and is involved in DNA-binding. The structure of HhaI methyltransferase (M.HhaI) has been resolved to 2.5 A [PMID: 8343957]: the molecule folds into 2 domains - a larger catalytic domain containing catalytic and cofactor binding sites, and a smaller DNA recognition domain.

GO terms

Biological Process

GO:0006306 DNA methylation

Molecular Function

GO:0003677 DNA binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns
PROSITE patterns