Imaging transcription complexes with the Atomic Force Microscope.
Recent developments in sample deposition and image analysis have shown that the Atomic Force Microscope is a valuable tool for the structural investigation of transcription complexes. When deposited under conditions that allow molecular equilibration onto the substrate, transcription complexes behave as worm-like chains and the mean square end-to-end distance can readily be used to determine the protein induced DNA bend angle. Measurements of the DNA contour length by means of accurate image processing procedures have revealed a DNA compaction in transcription complexes which is compatible with wrapping of the DNA against the surface of the RNA Polymerase. The methods presented have to be considered of general practical use for imaging protein-DNA complexes.
Rivetti
Claudio
C
Dipartimento di Biochimica e Biologia Molecolare, Università degli Studi di Parma, Parma, Italy. rivetti@unipr.it
Vannini
Nicola
N
Cellai
Sara
S
D004247:DNA / Q000737:chemistry; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D018625:Microscopy, Atomic Force; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
D004247:DNA; D012321:DNA-Directed RNA Polymerases