In vivo existence of left-handed DNA.
A genetic-biochemical assay has been developed to investigate the in vivo existence and consequences of unusual DNA structures. Left-handed DNA was shown to exist in living Escherichia coli. The EcoRI methyltransferase gene (temperature-sensitive) was cloned to serve as a probe for perturbed GAATTC sites in vivo. This plasmid was cotransformed with different plasmids containing inserts that had varying capacities to form left-handed helices or cruciforms with a target EcoRI 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 helices. In vitro methylation with the purified M.EcoRI enzyme agreed with the in vivo results.
Jaworski
A
A
Department of Biochemistry, School of Medicine, University of Alabama, Birmingham 35294.
Zacharias
W
W
Hsieh
W T
WT
Blaho
J A
JA
Larson
J E
JE
Wells
R D
RD
D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D004247:DNA / Q000032:analysis*; D004269:DNA, Bacterial / Q000378:metabolism / Q000648:ultrastructure*; D004274:DNA, Recombinant / Q000378:metabolism; D007700:Kinetics; D008745:Methylation; D009690:Nucleic Acid Conformation; D010957:Plasmids; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific) / Q000378:metabolism*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004274:DNA, Recombinant; D004247:DNA; C020098:DNA modification methylase EcoRI; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific)