Fluorescence label studies of the phase transitions of T7

J. Fidy, Y. Mauss, K. Pataki, J. Chambron, Gy Rontó

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3 Citations (Scopus)


Optical density, fluorescence intensity, polarization and lifetime measurements were performed to analyze the temperature-induced phase transitions of phage T7 in several buffers. For labelling the intraphage DNA, ethidium bromide, proflavine and rivanol were applied for the proteins 1,6-diphenyl-1,3,5-hexatriene (DPH). In the temperature range of 20‡C-100‡C several structural changes of T7 were detected. Making corrections for light scattering by using integrating spheres and analyzing the fluorescence signals, the phase transition of intraphage DNA below 60‡ C was interpreted as a superhelical relaxation phenomenon. The structural changes found by optical density at higher temperatures could be assigned to a change in the phage DNA or to a change in its protein part on the basis of fluorescence-melting results concerning DNA and protein labels. The effects of ionic strength and environment on the structural changes were studied.

Original languageEnglish
Pages (from-to)109-119
Number of pages11
JournalBiophysics of Structure and Mechanism
Issue number3
Publication statusPublished - Sep 1 1983


  • Acridine dyes
  • DPH bound to phage proteins
  • Light scattering corrected optical, and fluorescence melting
  • Phase transitions of phage T7
  • Superhelical structure

ASJC Scopus subject areas

  • Medicine(all)

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