Influence of phage proteins on formation of specific UV DNA photoproducts in phage T7

A. Fekete, A. A. Vink, S. Gaspar, K. Módos, A. Bérces, G. Rontó, L. Roza

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Phage T7 can be used as a biological UV dosimeter. Its reading is proportional to the inactivation rate expressed in HT7 units. To understand the influence of phage proteins on the formation of DNA UV photoproducts, cyclobutane pyrimidine dimers (CPD) and (6-4)photoproducts ((6-4)PD) were determined in T7 DNA exposed to UV radiation under different conditions: intraphage T7 DNA, isolated T7 DNA and heated phage. To investigate the effects of various wavelengths, seven different UV sources have been used. The CPD and (6-4)PD were determined by lesion-specific antibodies in an immunodotblot assay. Both photoproducts were HT7 dose-dependently produced in all three objects by every irradiation source in the biologically relevant UV dose range (1-10 HT7). The CPD to (6-4)PD ratios increased with the increasing effective wavelength of the irradiation source and were similar in intraphage T7 DNA, isolated DNA and heated phage with all irradiation sources. However, a significant decrease in the yield of both photoproducts was detected in isolated T7 DNA and in heated phage compared to intraphage DNA, the decrease was dependent on the irradiation source. Both photoproducts were affected the same way in isolated T7 DNA and heated phage, respectively. The yield of CPD and (6-4)PD was similar in B, C-like and A conformational states of isolated T7 DNA, indicating that the conformational switch in the DNA is not the decisive factor in photoproduct formation. The most likely explanation for modulation of photoproduct frequency in intraphage T7 DNA is that the presence of bound phage proteins induces an alteration in DNA structure that can result in an increased rate of dimerization and (6-4)PD production of adjacent bases in intraphage T7 DNA.

Original languageEnglish
Pages (from-to)545-552
Number of pages8
JournalPhotochemistry and Photobiology
Volume69
Issue number5
Publication statusPublished - May 1999

Fingerprint

Bacteriophage T7
Bacteriophages
deoxyribonucleic acid
proteins
DNA
Proteins
Pyrimidine Dimers
cyclobutane
pyrimidines
dimers
Irradiation
irradiation
Wavelength
dosage
Dimerization
Dosimeters
dimerization
antibodies
wavelengths
Ultraviolet radiation

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Biophysics

Cite this

Influence of phage proteins on formation of specific UV DNA photoproducts in phage T7. / Fekete, A.; Vink, A. A.; Gaspar, S.; Módos, K.; Bérces, A.; Rontó, G.; Roza, L.

In: Photochemistry and Photobiology, Vol. 69, No. 5, 05.1999, p. 545-552.

Research output: Contribution to journalArticle

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