title: Sequence specificity of DNA adenine methylase in the protozoan Tetrahymena thermophila.
abstract: The sequence specificity of the Tetrahymena DNA-adenine methylase was determined by nearest-neighbor analyses of in vivo and in vitro methylated DNA. In vivo all four common bases were found to the 5' side of N6-methyladenine, but only thymidine was 3'. Homologous DNA already methylated in vivo and heterologous Micrococcus luteus DNA were methylated in vitro by a partially purified DNA-adenine methylase activity isolated from Tetrahymena macronuclei. The in vitro-methylated sequence differed from the in vivo sequence in that both thymidine and cytosine were 3' nearest neighbors of N6-methyladenine.
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives; D000818:Animals; D001483:Base Sequence; D003596:Cytosine; D004247:DNA / Q000378:metabolism*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D008780:Methyltransferases / Q000378:metabolism*; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); D013379:Substrate Specificity; D013768:Tetrahymena / Q000201:enzymology*; D013936:Thymidine
chemical_list: D000225:Adenine; D003596:Cytosine; D004247:DNA; D004248:DNA (Cytosine-5-)-Methyltransferases; D004269:DNA, Bacterial; D008780:Methyltransferases; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); D013936:Thymidine; C000730567:6-methyladenine