DNA methylation in thermophilic bacteria: N4-methylcytosine, 5-methylcytosine, and N5methyladenine

Melanie Ehrlich, Miguel A. Gama-Sosa, Laura H. Carreira, Lars G. Ljungdahl, Kenneth C. Kuo, Charles W. Gehrke

Research output: Contribution to journalArticlepeer-review

112 Scopus citations


While determining the minor and major base composition of the DNA from 17 types of thermophilic bacteria by high performance liquid chromatography (HPLC) of enzymatic digests, we have discovered a novel base, N4-nethylcytosine (m4C) Its structure was proven by comparison of the DNA-derived nucleoside to the analogous authentic compound by HPLC, UV spectroscopy, and mass spectroscopy. Eight of the bacterial DNAs contained m4C. Only two contained the common minor base, 5-methylcytosine (m5C) and neither of these was from an extreme thermophile. The other prevalent modified base of bacterial DNA, N6-methyladenine (m6A) was found in nine of the DNAs. Restriction analysis revealed that four of the DNAs had dam-type (Gm6ATC) methylation patterns. Due to the propensity of m5 residues to be deaminatad by heat to thymine residues and to inefficient repair of the resulting mismatched base pairs, thermophiles with optimal growth temperatures of ≥60°C generally may avoid having m5C in their genomes. Instead, some of them have deamination-resistant m4C residues.

Original languageEnglish
Pages (from-to)1399-1412
Number of pages14
JournalNucleic Acids Research
Issue number4
StatePublished - 25 Feb 1985
Externally publishedYes


Dive into the research topics of 'DNA methylation in thermophilic bacteria: N4-methylcytosine, 5-methylcytosine, and N5methyladenine'. Together they form a unique fingerprint.

Cite this