PROSITE documentation PDOC00088
N-4 cytosine-specific DNA methylases signature


N-4 cytosine-specific DNA methylases (EC [1,2,3] are enzymes that specifically methylate the amino group at the C-4 position of cytosines in DNA. Such enzymes are found as components of type II restriction-modification systems in prokaryotes. Such enzymes recognize a specific sequence in DNA and methylate a cytosine in that sequence. By this action they protect DNA from cleavage by type II restriction enzymes that recognize the same sequence.

Type II N-4 Mtases seem to be structurally and enzymatically related to N-6 adenine-specific DNA methylases. Like the N-6 Mtases they contain a conserved Pro-Pro-Tyr/Phe region, but the N- and C-terminal contexts of this region are sufficiently different to derive a consensus pattern specific to this type of enzymes.

Expert(s) to contact by email:

Roberts R.J.
Bickle T.

Last update:

November 1997 / Text revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

N4_MTASE, PS00093; N-4 cytosine-specific DNA methylases signature  (PATTERN)


1AuthorsTao T. Walter J. Brennan K.J. Cotterman M.M. Blumenthal R.M.
TitleSequence, internal homology and high-level expression of the gene for a DNA-(cytosine N4)-methyltransferase, M.Pvu II.
SourceNucleic Acids Res. 17:4161-4175(1989).
PubMed ID2662138

2AuthorsKlimasauskas S. Timinskas A. Menkevicius S. Butkiene D. Butkus V. Janulaitis A.
TitleSequence motifs characteristic of DNA[cytosine-N4]methyltransferases: similarity to adenine and cytosine-C5 DNA-methylases.
SourceNucleic Acids Res. 17:9823-9832(1989).
PubMed ID2690010

3AuthorsTiminskas A. Butkus V. Janulaitis A.
TitleSequence motifs characteristic for DNA [cytosine-N4] and DNA [adenine-N6] methyltransferases. Classification of all DNA methyltransferases.
SourceGene 157:3-11(1995).
PubMed ID7607512

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