Left-handed DNA in vivo.
Left-handed DNA is shown to exist and elicit a biological response in Escherichia coli. A plasmid encoding the gene for a temperature-sensitive Eco RI methylase (MEco RI) was cotransformed with different plasmids containing inserts that had varying capacities to form left-handed helices or cruciforms with a target Eco RI site in the center or at the ends of the inserts. Inhibition of methylation in vivo was found for the stable inserts with the longest left-handed (presumably Z) helices. In vitro methylation with the purified MEco RI agreed with the results in vivo. Supercoil-induced changes in the structure of the primary helix in vitro provided confirmation that left-handed helices were responsible for this behavior. The presence in vivo of left-handed inserts elicits specific deletions and plasmid incompatibilities in certain instances.
Jaworski
A
A
Department of Biochemistry, School of Medicine, University of Alabama, Birmingham 35294.
Hsieh
W T
WT
Blaho
J A
JA
Larson
J E
JE
Wells
R D
RD
D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics*; D004278:DNA, Superhelical / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D007700:Kinetics; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D009690:Nucleic Acid Conformation; D010957:Plasmids; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific)
D004278:DNA, Superhelical; D004247:DNA; C020098:DNA modification methylase EcoRI; D008780:Methyltransferases; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific)