Conformational properties of B-Z junctions in DNA.
The structural consequences of specific base sequences in DNA can exert a strong influence on the function of DNA. It has previously been reported that the presence of multiple B-Z conformational junctions in constructed DNA oligomers results in unusually enhanced electrophoretic gel mobilities of these oligomers [Winkle, S. A., & Sheardy, R. D. (1990) Biochemistry 29, 6514-6521]. In order to investigate this phenomenon further, we designed and synthesized several DNA oligomers capable of pure Z or B-Z junction formation for polyacrylamide gel electrophoresis studies. The results indicate that both pure Z-DNA and polymorphic B-Z-DNA oligomers exhibit unusual gel migratory properties. The results of gel mobility studies in the absence and presence of cobalt hexamine indicate that a B-Z junction corresponds to a stiff bend of the helix axis, with two or more conformers accessible at the junction site. This is a different bend and mechanism than that in oligo(A) tracts.
Lu
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Department of Chemistry, New York University, New York 10003.
Guo
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Q
Kallenbach
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Sheardy
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RD
D001483:Base Sequence; D001665:Binding Sites; D002942:Circular Dichroism; D003035:Cobalt / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D009690:Nucleic Acid Conformation; D013329:Structure-Activity Relationship
C030862:cobalt ammonium complex; D003035:Cobalt; D004247:DNA