Photosensitized inactivation of T7 phage as surrogate of non-enveloped DNA viruses: Efficiency and mechanism of action

M. Egyeki, G. Turóczy, Zs Majer, K. Tóth, A. Fekete, Ph Maillard, G. Csík

Research output: Contribution to journalArticle

24 Citations (Scopus)


We investigated the efficiency and the mechanism of action of a tetraphenyl porphyrin derivative in its photoreaction with T7 phage as surrogate of non-enveloped DNA viruses. TPFP was able to sensitize the photoinactivation of T7 phage in spite of the lack of its binding to the nucleoprotein complex. The efficiency of TPFP photosensitization was limited by the aggregation and by the photobleaching of porphyrin molecules. Addition of sodium azide or 1,3-dimethyl-2-thiourea (DMTU) to the reaction mixture moderated T7 inactivation, however, neither of them inhibited T7 inactivation completely. This result suggests that both Type I and Type II reaction play a role in the virus inactivation. Optical melting studies revealed structural changes in the protein part but not in the DNA of the photochemically treated nucleoprotein complex. Polymerase chain reaction (PCR) also failed to demonstrate any DNA damage. Circular dichroism (CD) spectra of photosensitized nucleoprotein complex indicated changes in the secondary structure of both the DNA and proteins. We suggest that damages in the protein capsid and/or loosening of protein-DNA interaction can be responsible for the photodynamic inactivation of T7 phage. The alterations in DNA secondary structure might be the result of photochemical damage in phage capsid proteins.

Original languageEnglish
Pages (from-to)115-124
Number of pages10
JournalBiochimica et Biophysica Acta - General Subjects
Issue number1-3
Publication statusPublished - Dec 5 2003


  • Photodynamic virus inactivation
  • T7 phage
  • Tetraphenyl porphyrin

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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