Bacteriophage φ6-structure investigated by fluorescence stokes shift Spectroscopy

Alvin Katz, Alexandra Alimova, Elina Futerman, Garrett Katz, Hui Wei, Paul Gottlieb

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


The Stokes shift of tryptophan (Trp) fluorescence from layers of the lipid-containing bacteriophage φ6 is compared to determine the relative effect of the layers on virus hydrophobicity. In the inner most layer, the empty procapsid (PC) which contains 80-90% of the virion Trp residues, λ max = 339.8 nm. The PC emission is substantially more redshifted than the other φ6 layers and nearer to that of the Pseudomonad host cell than the other φ6 layers. The Trp emission from the nucleocapsid (NC) with λ max = 337.4 nm, is blueshifted by 2.4 nm relative to the PC although the number of Trp in the NC is identical to the PC. This shift represents an increase in Trp hydrophobicity, likely a requirement for the maintenance of A-form doubled-stranded RNA. Fluorescence from the completely assembled virion indicates it is in a considerably more hydrophobic environment with λ max = 330.9 nm. Density measurements show that the water content in the NC does not change during envelope assembly, therefore the blueshifted φ6 emission suggests that the envelope changes the PC environment, probably via the P8 layer. This change in hydrophobicity likely arises from charge redistribution or envelope-induced structural changes in the PC proteins.

Original languageEnglish (US)
Pages (from-to)304-310
Number of pages7
JournalPhotochemistry and photobiology
Issue number2
StatePublished - Mar 2012
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry


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