SEDIMENTATION AND CONFORMATIONAL VARIANCE AMONG T-EVEN BACTERIOPHAGES

The effect of adsorption cofactors and ionic strength on the sedimentation behavior of T-even bacteriophages was examined. It was found that while indole or l-tryptophan had no effect on the adsorption properties of T2L or T6, these compounds had marked effects on the bacteriophages' sedimentation behavior. Indole mediated a transition from the 700 S form of T2L to both an 800 S and a 900 S form, and l-tryptophan mediated a transition from the 1000 S form of T6 to an 800 S form. At increasingly higher ionic strengths, the 900 S form of T4B, T4B01, and T4D was gradually transformed to a 700 S form. High ionic strength solutions maintained T2L and T6 in the 1000 S form. A morphological basis of all these sedimentation forms was presented. An essential feature of this involved changes in head configuration. The sedimentation behavior of free heads from either amber or wild-type bacteriophage was also investigated and it was found that free heads exhibited two sedimentation coefficients differing by about 46%. This behavior was related to the sedimentation properties of intact phage particles and indicated that the head could undergo configurational changes. © 1969.