Sequence motifs characteristic for DNA [cytosine-N4] and DNA [adenine-N6] methyltransferases. Classification of all DNA methyltransferases

Timinskas, Albertas; Butkus, Viktoras; Janulaitis, A.

doi:10.1016/0378-1119(94)00783-o

Cited by 99 publications

(87 citation statements)

References 20 publications

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“…Although both adenine and cytosine DNA MTases show a degree of similarity in their architectural plan, there are important differences (8). Conservation of sequence is more prominent among members of the m5C-DNA MTase family than among those belonging to the N 6 -adenine DNA MTase family (8). Kinetics of methyl transfer by M.HhaI (m5C-MTase) and M.EcoRI (N 6 -adenine MTase) has been elucidated (9, 10).…”

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confidence: 99%

Kinetic Mechanism of Cytosine DNA MethyltransferaseMspI

Bhattacharya

Dubey²

1999

Journal of Biological Chemistry

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confidence: 99%

Kinetic Mechanism of Cytosine DNA MethyltransferaseMspI

Bhattacharya

Dubey²

1999

Journal of Biological Chemistry

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“…Perfectly conserved residues are indicated by an asterisk, conservative residue substitutions by two dots, and semi-conservative substitutions by one dot. Conserved motifs (CM) found in methyltransferases are shown in bold according to Timinskas et al (1995). The CM I and CM II, and possibly the CM Is, motifs are thought to be involved in AdoMet binding and methyl-group transfer in class N methyltransferases (Timinskas et al, 1995).…”

Section: Expression Of Cloned Sau42i R-m Genes In S Aureus Confers Rmentioning

confidence: 99%

“…Conserved motifs (CM) found in methyltransferases are shown in bold according to Timinskas et al (1995). The CM I and CM II, and possibly the CM Is, motifs are thought to be involved in AdoMet binding and methyl-group transfer in class N methyltransferases (Timinskas et al, 1995). The DXXXGXG (where X is any amino acid) and NPPY submotifs present in CM I and CM II, respectively, are underlined.…”

Section: Expression Of Cloned Sau42i R-m Genes In S Aureus Confers Rmentioning

confidence: 99%

“…One of the advantages of R-M systems over mutations conferring phage resistance is that one R-M system can simultaneously protect against a variety of phages, thus giving the host an advantage over competing organisms. In general, bacterial R-M systems consist of a restriction endonuclease (responsible for recognition of, and cleavage within, a specific DNA sequence) and a DNA methyltransferase (which modifies unmethylated or hemimethylated DNA within the same sequence) (Wilson & Murray, 1991;Cheng, 1995;Malone et al, 1995;Timinskas et al, 1995). Restriction endonucleases usually require Mg 2+ or other divalent cations in order to cleave DNA.…”

Section: Introductionmentioning

confidence: 99%

“…Some also require, or are stimulated by, ATP or Sadenosylmethionine (AdoMet). Modification methyltransferases require AdoMet as a co-factor, which serves as the methyl donor (Wilson & Murray, 1991;Cheng, 1995;Malone et al, 1995;Timinskas et al, 1995). In some R-M systems, the restriction endonuclease can operate independently of the modification machinery, while other systems require both the restriction and modification components in order to function (Wilson & Murray, 1991).…”

Section: Introductionmentioning

confidence: 99%

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Sau42I, a BcgI-like restriction–modification system encoded by the Staphylococcus aureus quadruple-converting phage π42

et al. 2005

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The serotype F phage w42 of Staphylococcus aureus is a triple-converting bacteriophage that encodes the staphylokinase gene (sak) and the enterotoxin A gene (entA). Lysogeny results in loss of expression of the chromosomal b-haemolysin gene (hlb) (negative conversion), the expression of staphylokinase and enterotoxin A (positive conversion), and the acquisition of resistance to lysis by all 23 phages of the International Basic Set (IBS) of S. aureus typing phages. Until this study, the basis of w42 resistance to lysis by exogenous phages was unknown. The authors report here that phage w42 encodes a restriction-modification (R-M) system, termed Sau42I, adjacent to and in the same orientation to the phage integrase gene int. The genes encoding Sau42I were cloned and sequenced, and found to consist of two overlapping reading frames, ORF S (specificity) and ORF RM (restriction-modification), in the same orientation. The ORFs share a high degree of DNA and amino acid sequence homology with the previously characterized BcgI R-M system of Bacillus coagulans. Expression of the cloned Sau42I ORF S and ORF RM in S. aureus 80CR3 transformants from a plasmid vector conferred resistance to lysis by all 23 IBS phages. Similarly, transformants of S. aureus RN4220 harbouring recombinant plasmids containing both ORFs were resistant to lysis by the IBS typing phages. However, transformants harbouring plasmids encoding either ORF S or ORF RM were susceptible to lysis by the IBS phages, and they had the same phage-susceptibility pattern as the respective parental isolates. In vitro analysis of crude and partially purified extracts of S. aureus transformants harbouring both the w42 ORF S and ORF RM genes indicated that Sau42I has endonuclease activity and requires co-factors Mg 2+ and S-adenosylmethionine in order to function, and activity is optimized at pH 8, although the precise recognition sequence has yet to be determined. The findings of this study confirm that w42 is a quadruple-converting phage, believed to be the first described for S. aureus, and show that it encodes a novel R-M system termed Sau42I.

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Agronomy III: Molecular Biology

Stiles¹

2001

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Sequence motifs characteristic for DNA [cytosine-N4] and DNA [adenine-N6] methyltransferases. Classification of all DNA methyltransferases

Cited by 99 publications

References 20 publications

Kinetic Mechanism of Cytosine DNA MethyltransferaseMspI

Kinetic Mechanism of Cytosine DNA MethyltransferaseMspI

Sau42I, a BcgI-like restriction–modification system encoded by the Staphylococcus aureus quadruple-converting phage π42

Agronomy III: Molecular Biology

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