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Titolo:
SUPERHELIX DIMENSIONS OF A 1868 BASE-PAIR PLASMID DETERMINED BY SCANNING FORCE MICROSCOPY IN AIR AND IN AQUEOUS-SOLUTION
Autore:
RIPPE K; MUCKE N; LANGOWSKI J;
Indirizzi:
DEUTSCH KREBSFORSCHUNGSZENTRUM,ABT BIOPHYS MAKROMOL,NEUENHEIMER FELD 280 D-69120 HEIDELBERG GERMANY
Titolo Testata:
Nucleic acids research
fascicolo: 9, volume: 25, anno: 1997,
pagine: 1736 - 1744
SICI:
0305-1048(1997)25:9<1736:SDOA1B>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
SUPERCOILED DNA; CIRCULAR DNA; COMPLEXES; TRANSCRIPTION; MOLECULES; MICA; VISUALIZATION; HELICES; LIQUID; SALT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
49
Recensione:
Indirizzi per estratti:
Citazione:
K. Rippe et al., "SUPERHELIX DIMENSIONS OF A 1868 BASE-PAIR PLASMID DETERMINED BY SCANNING FORCE MICROSCOPY IN AIR AND IN AQUEOUS-SOLUTION", Nucleic acids research, 25(9), 1997, pp. 1736-1744

Abstract

We have used scanning force microscopy (SFM) to study the conformation of a 1868 base pair plasmid (p1868) in its open circular form and ata superhelical density of sigma = -0.034. The samples were deposited on a mica surface in the presence of MgCl2. DNA images were obtained both in air and in aqueous solutions, and the dimensions of the DNA superhelix were analysed. Evaluation of the whole plasmid yielded averagesuperhelix dimensions of 27 +/- 9 nm (outer superhelix diameter D), 107 +/- 51 nm (superhelix pitch P), and 54 +/- 8 degrees (superhelix pitch angle alpha). We also analysed compact superhelical regions withinthe plasmid separately, and determined values of D = 9.2 +/- 3.3 nm, P = 42 +/- 13 nm and alpha = 63 +/- 20 degrees for samples scanned in air or rehydrated in water. These results indicate relatively large conformation changes between superhelical and more open regions of the plasmid. In addition to the analysis of the DNA superhelix dimensions, we have followed the deposition process of open circular p1868 to micain real time, These experiments show that it is possible to image DNAsamples by SFM without prior drying, and that the surface bound DNA molecules retain some ability to change their position on the surface.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/10/20 alle ore 11:58:40