Evidence of DNA bending in transcription complexes imaged by scanning force microscopy.
Complexes of Escherichia coli RNA polymerase with DNA containing the lambda PL promoter have been deposited on mica and imaged in air with a scanning force microscope. The topographic images reveal the gross spatial relations of the polymerase relative to the DNA template. The DNA appears bent in open promoter complexes containing RNA polymerase bound to the promoter and appears more severely bent in elongation complexes in which RNA polymerase has synthesized a 15-nucleotide transcript. This difference could be related to the conformational changes that accompany the maturation of open promoter complexes into elongation complexes and suggests that formation of the elongation complex involves a considerable modification of the spatial relations between the polymerase and the DNA template.
Institute of Molecular Biology, University of Oregon, Eugene 97403.
W A
WA
Rees
R W
RW
Keller
J P
JP
Vesenka
G
G
Yang
C
C
Bustamante
D004247:DNA / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology; D008853:Microscopy / Q000379:methods; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D013698:Templates, Genetic; D013816:Thermodynamics; D014158:Transcription, Genetic
D004247:DNA; D012321:DNA-Directed RNA Polymerases