title: Specificities of eleven different DNA methyltransferases of Helicobacter pylori strain 26695.
abstract: Methyltransferases (MTases) of procaryotes affect general cellular processes such as mismatch repair, regulation of transcription, replication, and transposition, and in some cases may be essential for viability. As components of restriction-modification systems, they contribute to bacterial genetic diversity. The genome of Helicobacter pylori strain 26695 contains 25 open reading frames encoding putative DNA MTases. To assess which MTase genes are active, strain 26695 genomic DNA was tested for cleavage by 147 restriction endonucleases; 24 were found that did not cleave this DNA. The specificities of 11 expressed MTases and the genes encoding them were identified from this restriction data, combined with the known sensitivities of restriction endonucleases to specific DNA modification, homology searches, gene cloning and genomic mapping of the methylated bases m(4)C, m(5)C, and m(6)A.
authors.affiliation: Institute of Biotechnology, Graiciuno 8, LT-2028 Vilnius, Lithuania.
authors.forename: J
authors.initials: J
authors.lastname: Vitkute
authors.forename: K
authors.initials: K
authors.lastname: Stankevicius
authors.forename: G
authors.initials: G
authors.lastname: Tamulaitiene
authors.forename: Z
authors.initials: Z
authors.lastname: Maneliene
authors.forename: A
authors.initials: A
authors.lastname: Timinskas
authors.forename: D E
authors.initials: DE
authors.lastname: Berg
authors.forename: A
authors.initials: A
authors.lastname: Janulaitis
mesh_terms: D003001:Cloning, Molecular; D015254:DNA Modification Methylases / Q000378:metabolism*; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism; D005798:Genes, Bacterial; D016480:Helicobacter pylori / Q000201:enzymology*; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D004269:DNA, Bacterial; D015254:DNA Modification Methylases; D008780:Methyltransferases; D004262:DNA Restriction Enzymes