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Quasielastic light scattering from solutions of filamentous viruses. I. Experimental
Author(s) -
Loh Eugene,
Ralston Edward,
Schumaker Verne N.
Publication year - 1979
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.1979.360181013
Subject(s) - diffusion , rotational diffusion , chemistry , exponential decay , amplitude , scattering , fick's laws of diffusion , anisotropy , molecular physics , light scattering , coupling constant , physics , atomic physics , optics , nuclear physics , quantum mechanics
Abstract Intensity fluctuations of laser light scattered from filamentous viruses Pf1 [length L (Å) × diameter d (Å) = 20,000 × 90], M13 (9000 × 90), potato virus X (5150 × 130), and tobacco mosaic virus (3000 × 180) in sucrose density gradients were measured with a photon correlation spectrometer over a range of scattering angles from 15° to 120°. The experimental data can be approximated by two exponential decays, “slow” and “fast.” The slow decay rate constant t s −1corresponds to the translational diffusion D of the virus, i.e., t s −1= K 2 D , where K is the magnitude of the scattering vector. The amplitude of the slow component, i.e., translational diffusion, remains greater than that of the fast component, even at high KL . The fast decay rate constant t f −1is also proportional to K 2 for viruses such as Pf1, M13, and even potato virus X. In the companion paper, we shall attribute the amplitude enhancement of the translational diffusion to the coupling of its anisotropy to the rotational diffusion modes. In order to explain the excessive decay rates in the fast component, we need to consider the bending mode of rodlike viruses, especially in the longer viruses such as M13 and Pf1, in addition to the usually expected rotational diffusion modes.