Characterization of monomers and small assemblies of tobacco mosaic virus proteins using the electric birefringence method

Abstract

1. 1.|The electric birefringence of monomers and oligomers of proteins from the ordinary strain of tobacco mosaic virus (TMV-O) and from the bean strain of TMV (TMV-B) was measured using the high rectangular pulse method. 2. 2.|The specific Kerr constants for monomers of both proteins in 33% acetic acid were about 2·10 −8 e.s.u. The specific Kerr constant for the oligomer of the TMV-O protein in a 5 mM phosphate buffer (pH 7.0) was of the same order as for these monomers, while that for the TMV-B protein in the same solvent condition was two or three times larger (5.0·10 −8 e.s.u.). 3. 3.|The relaxation time of birefringence was about 0.025–0.030 μsec for monomers and about 0.140–0.150 μsec for oligomers. 4. 4.|The oligomer of the TMV-B protein was distinguished from that of the TMV-B protein by the contribution of the permanent dipole moment to the electric birefringence. Some qualitative difference between the proteins in the process of constructing oligomers from monomers was suggested.