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Transient electric birefringence of T‐even bacteriophages. I. T4B in the absence of tryptophan and fiberless T4 particles
Author(s) -
Greve J.,
Block Joh.
Publication year - 1973
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1973.360121113
Subject(s) - chemistry , rotational diffusion , birefringence , electric field , debye , dipole , diffusion , moment (physics) , particle (ecology) , analytical chemistry (journal) , molecular physics , nuclear magnetic resonance , thermodynamics , optics , chromatography , physics , classical mechanics , oceanography , organic chemistry , quantum mechanics , molecule , geology
Measurements of the electric birefringence of suspensions of T4B in the absence of tryptophan and of fiberless T4 particles show that both kinds of particles are hydrodynamically equivalent. Their rotational diffusion coefficients corrected to 25°C and water viscosity ( D 25,w ) are 280 ± 9 sec −1 and 295 ± 10 sec −1 , respectively. These corrected rotational diffusion coefficients are almost independent of buffer concentration and temperature. The sedimentation coefficient ( s 20,w ) of T4 B is equal to 1023 ± 12 S, a value which is likewise independent of buffer concentration. By analysis of the field strength dependence of the steady‐state birefringence and by reversing pulse experiments it could be shown that the orientation in an electric field is largely due to a permanent dipole moment. This dipole moment is somewhat dependent on buffer concentration and amounts to about 24,000 debye for T4B and 95,000 debye for fiberless T4. An approximate calculation shows that the difference in dipole moment may be ascribed to positive charges on the fiber tip (at least ten per fiber), to negative charges along the fiber or (and) positive charges on the fiberless particle at those places where the fibers are attached in normal particles.