{PDOC00089} {PS00094; C5_MTASE_1} {PS00095; C5_MTASE_2} {BEGIN} *************************************************** * C-5 cytosine-specific DNA methylases signatures * *************************************************** C-5 cytosine-specific DNA methylases (EC 2.1.1.37) (C5 Mtase) are enzymes that specifically methylate the C-5 carbon of cytosines in DNA [1,2,3]. 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 recognize a specific DNA sequence where they methylate a cytosine. In doing so, they protect DNA from cleavage by type II restriction enzymes that recognize 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. We selected two of them. The first is centered around a conserved Pro-Cys dipeptide in which the cysteine has been shown [4] to be involved in the catalytic mechanism; it appears to form a covalent intermediate with the C6 position of cytosine. The second region is located at the C-terminal extremity in type-II enzymes. -Consensus pattern: [DENKS]-x-[FLIV]-x(2)-[GSTC]-x-P-C-x-{V}-[FYWLIM]-S [C is the active site residue] -Sequences known to belong to this class detected by the pattern: ALL, except for M.MthtI. -Other sequence(s) detected in Swiss-Prot: 3. -Consensus pattern: [RKQGTF]-x(2)-G-N-[SA]-[LIVF]-x-[VIP]-x-[LVMT]-x(3)- [LIVM]-x(3)-[LIVM] -Sequences known to belong to this class detected by the pattern: ALL, except for M.AluI, M.HgaI 1 and 2, and M.HpaII. -Other sequence(s) detected in Swiss-Prot: 2. -Note: In the first position of the second pattern, most known Mtases have Arg or Lys. -Expert(s) to contact by email: Roberts R.J.; roberts@neb.com Bickle T.; bickle@ubaclu.unibas.ch Mugasimangalam R.; genotypic@hotmail.com -Last update: December 2004 / Pattern and text revised. [ 1] Posfai J., Bhagwat A.S., Roberts R.J. "Sequence motifs specific for cytosine methyltransferases." Gene 74:261-265(1988). PubMed=3248729 [ 2] Kumar S., Cheng X., Klimasauskas S., Mi S., Posfai J., Roberts R.J., Wilson G.G. "The DNA (cytosine-5) methyltransferases." Nucleic Acids Res. 22:1-10(1994). PubMed=8127644 [ 3] Lauster R., Trautner T.A., Noyer-Weidner M. "Cytosine-specific type II DNA methyltransferases. A conserved enzyme core with variable target-recognizing domains." J. Mol. Biol. 206:305-312(1989). PubMed=2716049 [ 4] Chen L., MacMillan A.M., Chang W., Ezaz-Nikpay K., Lane W.S., Verdine G.L. "Direct identification of the active-site nucleophile in a DNA (cytosine-5)-methyltransferase." Biochemistry 30:11018-11025(1991). PubMed=1932026 -------------------------------------------------------------------------------- PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html -------------------------------------------------------------------------------- {END}