Evolution of type II DNA methyltransferases

Lauster, Roland

doi:10.1016/0022-2836(89)90481-6

Cited by 107 publications

(87 citation statements)

References 44 publications

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“…Comparison of the sequences has revealed a remarkable similarity among the m5C MTases [2][3][4], which are readily distinguishable from the other two classes of MTases. The latter groups, however, also share similarities with each other, but these are not as pronounced as those found among the mSC MTases [5][6][7][8]. The maC and N6A MTases methylate an exocyclic amino nitrogen, whereas mSC MTases methylate a ring carbon.…”

Section: Introductionmentioning

confidence: 91%

Function of Pro‐185 in the ProCys of conserved motif IV in the EcoRII [cytosine‐C5]‐DNA methyltransferase

1995

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ProCys in the conserved sequence motif IV of [cytosine-C5]-DNA methyltransferases is known to be part of the catalytic site. The Cys residue is directly involved in forming a covalent bond with the C6 of the target cytosine. We have found that substitution of Pro-185 with either Ala or Ser resulted in a reduced rate of methyl group transfer by the EcoRII DNA methyltransferase. In addition, we observed an increase in the K m for substrate S-adenosyI-L-methionine (AdoMet), but a decrease in the Kn, for substrate DNA. This is reflected in minor changes in kc,,tIK m for DNA, but in 10-to 100-fold reductions in kcatlK m for AdoMet. This suggests that Pro-185 is important to properly orient the activated cytosine and AdoMet for methyl group transfer by direct interaction with AdoMet and indirectly via the Cys interaction with cytosine.

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Section: Introductionmentioning

confidence: 91%

Function of Pro‐185 in the ProCys of conserved motif IV in the EcoRII [cytosine‐C5]‐DNA methyltransferase

1995

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“…As a result, a constant coevolutionary process is operational between bacteria and phages. In order to counter phage invasions, R-M systems seem to evolve faster (191,192) and, hence, are frequently exchanged between species (95,193). In such a scenario, genes which hinder phage infection would be selected and are fixed in the population.…”

Section: Evolution Of Moonlighting Roles In R-m Systemsmentioning

confidence: 99%

Diverse Functions of Restriction-Modification Systems in Addition to Cellular Defense

Vasu

Nagaraja

2013

Microbiol Mol Biol Rev

507

481

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SUMMARY Restriction-modification (R-M) systems are ubiquitous and are often considered primitive immune systems in bacteria. Their diversity and prevalence across the prokaryotic kingdom are an indication of their success as a defense mechanism against invading genomes. However, their cellular defense function does not adequately explain the basis for their immaculate specificity in sequence recognition and nonuniform distribution, ranging from none to too many, in diverse species. The present review deals with new developments which provide insights into the roles of these enzymes in other aspects of cellular function. In this review, emphasis is placed on novel hypotheses and various findings that have not yet been dealt with in a critical review. Emerging studies indicate their role in various cellular processes other than host defense, virulence, and even controlling the rate of evolution of the organism. We also discuss how R-M systems could have successfully evolved and be involved in additional cellular portfolios, thereby increasing the relative fitness of their hosts in the population.

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“…On the other hand, if avoidance is more important on phages than on bacteria, one may think that the defense role of RMSs carries a sufficient advantage to be maintained in the population. Note, that for this discussion we consider that phages, bacteria, and RMSs have coevolved for a long time, which seems reasonable (Lauster 1989;Hendrix et al 1999).…”

mentioning

confidence: 99%

“…Although genes dealing with information processing are rarely horizontally transferred (Jain et al 1999) and evolve slowly (Woese 1998), RMSs seem to be very frequently exchanged between species (Kita et al 1999;Kobayashi et al 1999;Rocha et al 1999), and to evolve very quickly (Lauster 1989;Jeltsch and Pingoud 1996). This transfer is so frequent that more than 50 different RMSs specificities among natural strains of Escherichia coli have already been found (Roberts and Macelis 2000).…”

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confidence: 99%

Evolutionary Role of Restriction/Modification Systems as Revealed by Comparative Genome Analysis

Rocha¹

2001

Genome Research

107

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Type II restriction modification systems (RMSs) have been regarded either as defense tools or as molecular parasites of bacteria. We extensively analyzed their evolutionary role from the study of their impact in the complete genomes of 26 bacteria and 35 phages in terms of palindrome avoidance. This analysis reveals that palindrome avoidance is not universally spread among bacterial species and that it does not correlate with taxonomic proximity. Palindrome avoidance is also not universal among bacteriophage, even when their hosts code for RMSs, and depends strongly on the genetic material of the phage. Interestingly, palindrome avoidance is intimately correlated with the infective behavior of the phage. We observe that the degree of palindrome and restriction site avoidance is significantly and consistently less important in phages than in their bacterial hosts. This result brings to the fore a larger selective load for palindrome and restriction site avoidance on the bacterial hosts than on their infecting phages. It is then consistent with a view where type II RMSs are considered as parasites possibly at the verge of mutualism. As a consequence, RMSs constitute a nontrivial third player in the host-parasite relationship between bacteria and phages.Classic type II restriction modification systems (RMSs) comprise pairs of enzymes with matching DNA sequence specificity. The modification enzyme is a DNA methyltransferase that specifically methylates either adenosyl or cytosyl residues within the recognition sequence (the restriction site; RS), thus making DNA resistant to the restriction activity. The restriction enzyme is an endodeoxyribonuclease that cleaves DNA at a precise location within or around the recognition sequence, when this sequence is not methylated (Redaschi and Bickle 1996). These recognition sequences are symmetrical, comprising 4-8 specific base pairs, and cleavage and methylation occur symmetrically within the sequences. As a consequence, foreign double stranded DNA (dsDNA), unmethylated at the restriction sites recognized by the cell's RMS, is quickly degraded.

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Evolution of type II DNA methyltransferases

Cited by 107 publications

References 44 publications

Function of Pro‐185 in the ProCys of conserved motif IV in the EcoRII [cytosine‐C5]‐DNA methyltransferase

Function of Pro‐185 in the ProCys of conserved motif IV in the EcoRII [cytosine‐C5]‐DNA methyltransferase

Diverse Functions of Restriction-Modification Systems in Addition to Cellular Defense

Evolutionary Role of Restriction/Modification Systems as Revealed by Comparative Genome Analysis

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