>TIGR00571 dam DNA adenine methylase; InterPro: IPR012326 In prokaryotes, the major role of DNA methylation is to protect host DNA against degradation by restriction enzymes. There are 2 major classes of DNA methyltransferase that differ in the nature of the modifications they effect. The members of one class (C-MTases) methylate a ring carbon and form C5-methylcytosine (see IPR001525 from INTERPRO). Members of the second class (N-MTases) methylate exocyclic nitrogens and form either N4-methylcytosine (N4-MTases) or N6-methyladenine (N6-MTases). Both classes of MTase utilise the cofactor S-adenosyl-L-methionine (SAM) as the methyl donor and are active as monomeric enzymes . N-6 adenine-specific DNA methylases (2.1.1.72 from EC) (A-Mtase) are enzymes that specifically methylate the amino group at the C-6 position of adenines in DNA. Such enzymes are found in the three existing types of bacterial restriction-modification systems (in type I system the A-Mtase is the product of the hsdM gene, and in type III it is the product of the mod gene). All of these enzymes recognize a specific sequence in DNA and methylate an adenine in that sequence. It has been shown , , , that A-Mtases contain a conserved motif Asp/Asn-Pro-Pro-Tyr/Phe in their N-terminal section, this conserved region could be involved in substrate binding or in the catalytic activity. The structure of N6-MTase TaqI (M.TaqI) has been resolved to 2.4 A . The molecule folds into 2 domains, an N-terminal catalytic domain, which contains the catalytic and cofactor binding sites, and comprises a central 9-stranded beta-sheet, surrounded by 5 helices; and a C-terminal DNA recognition domain, which is formed by 4 small beta-sheets and 8 alpha-helices. The N- and C-terminal domains form a cleft that accommodates the DNA substrate. A classification of N-MTases has been proposed, based on conserved motif (CM) arrangements . According to this classification, N6-MTases that have a DPPY motif (CM II) occuring after the FxGxG motif (CM I) are designated D12 class N6-adenine MTases.; GO: 0009007 site-specific DNA-methyltransferase (adenine-specific) activity, 0006306 DNA methylation.

Probab=91.82  E-value=0.12  Score=30.62  Aligned_cols=61  Identities=25%  Similarity=0.363  Sum_probs=41.8

Q ss_pred             HHHHHHHHHHCCCCCCCC---CEEEECCCCCCCCHHHHHCCC--CCCHHHHHHHHHHHH---HHHHHHC
Q ss_conf             999998776333645589---678611001222100110168--733011100012356---6764200
Q gi|254780405|r   32 KKALFDILTHVYPVFLDS---TRMLNIFAGTGSVGFEALSRG--CHYVLFVDNNSESIR---LIRRNSE   92 (189)
Q Consensus        32 realFniL~~~~~~~~~~---~~vlDlfaGsG~lgiEalSrG--A~~v~~vE~~~~a~~---~lk~N~~   92 (189)
T Consensus        11 K~~Ll~~i~~~lPk~~~~~~~~~~vEPFvGgGAv~~~~~~~~~~lk~~~l~DiN~dLi~~Y~~~k~~~~   79 (327)
T TIGR00571        11 KTSLLPEIKKHLPKDFNESNIKCLVEPFVGGGAVFFNLNPKREELKDVLLSDINEDLINLYKAIKNNVD   79 (327)
T ss_pred             CHHHHHHHHHHCCCCCCCCCCCEEECCCCCHHHHHHHHCCCCCCCCEEEEECCCHHHHHHHHHHHCCCH
T ss_conf             776789999855524577763045347641778876642687113401453288779999999825855