Filamentous bacteriophage stability in non-aqueous media.

BACKGROUND: Filamentous bacteriophage are used as general cloning vectors as well as phage display vectors in order to study ligand-receptor interactions. Exposure to biphasic chloroform-water interface leads to specific contraction of phage, to non-infective I- or S-forms. RESULTS: Upon exposure, phage were inactivated (non-infective) at methanol, ethanol and 1-propanol concentrations inversely dependent upon alcohol hydrophobicity. Infectivity loss of phage at certain concentrations of 1-propanol or ethanol coincided with changes in the spectral properties of the f1 virion in ultraviolet fluorescence and circular dichroism studies. CONCLUSIONS: The alcohols inactivate filamentous phage by a general mechanism--solvation of coat protein--thereby disrupting the capsid in a manner quite different from the previously reported I- and S-forms. The infectivity retention of phagemid pG8H6 in 99% acetonitrile and the relatively high general solvent resistance of the phage strains studied here open up the possibility of employing phage display in non-aqueous media.