title: In-vivo-modified gonococcal plasmid pJD1. A model system for analysis of restriction enzyme sensitivity to DNA modifications.
abstract: The 4207-bp cryptic plasmid (pJD1) of Neisseria gonorrhoeae has 5-methylcytosine bases present at several positions in the DNA sequence. Fortuitously, these modified bases lie in the recognition sequences of many restriction enzymes. This feature makes the cryptic plasmid a model system for assaying the effect of these modified cytosines on the activities of the following restriction endonucleases and their isoschizomers: R X AvaII, R X BamHI, R X BglI, R X Fnu4HI, R X HaeII, R X HaeIII, R X HhaI, R X HpaII, R X KpnI, R X MspI, R X NaeI, R X NarI, R X NciI, R X NgoI, R X NgoII, and R X Sau96I. Of particular interest was the finding that methylation of one of the external cytosines of the palindrome 5'-CCGG-3' prevented its cleavage by R X MspI, but not by R X HpaII as had been suggested by Walder et al. [J. Biol. Chem. (1983) 258, 1235-1241].
mesh_terms: D044503:5-Methylcytosine; D001483:Base Sequence; D001665:Binding Sites; D002876:Chromosomes, Bacterial / Q000378:metabolism; D003596:Cytosine / Q000031:analogs & derivatives; D004262:DNA Restriction Enzymes / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism*; D009344:Neisseria gonorrhoeae / Q000235:genetics; D010957:Plasmids
chemical_list: D004269:DNA, Bacterial; D044503:5-Methylcytosine; D003596:Cytosine; D004262:DNA Restriction Enzymes