Light Diffraction of in vitro Crystals of Six Tobacco Mosaic Viruses

Abstract

Iridescent gels of the common, tomato mosaic, para-tobacco mosaic, ribgrass mosaic, sunnhemp mosaic, and cucumber 4 tobacco mosaic virus strains were prepared using the purification method of Boedtker and Simmons (J. Amer. Chem. Soc. 1958). Macrocrystals which were stable for many months could be grown from iridescent gels of all viruses when stored at 0-10 °C. The gels exhibited various structural phases (nematic and smectic) differing in density. The structure of the microcrystalline gels and of macrocrystals was investigated by means of optical diffraction. Distinct Bragg reflections were observed from which a mean periodicity of 340 nm was derived for all virus strains. The results indicate a crystalline multilayer structure as first proposed by Oster (J. Gen. Physiol. 33, 445, [1950]). The angular positions and widths of the Bragg reflections depended on the concentration of virus and the ionic strength. The periodicity decreased from 365 nm at 30 mg/ml virus to about 315 nm at 109 mg/ml virus, i.e. the periodicity approached the 300 nm length of the virion. Model calculations taking into account Debye-Hückel repulsive and van der Waals attractive forces gave a qualitative explanation for the crystalline structure and its observed concentration dependence. The in vitro crystals resemble immature crystal forms observed in the living cell.

Effect of electrostatic interaction on the liquid crystal phase transition in solutions of rodlike polyelectrolytes

“…19, No. 8,1986 that one has to integrate the exponent in eq 44 from x = D to a, which yields B2,el(sin $) = 2L2 sin $Jm(l -e-w/kBT) dx = (44) as can be seen from eq 1. Here, x is the shortest distance between the lines and 4 is the angle between them. In a calculation of the electrostatic excluded volume we stress This expression which holds for A' 2 2 has been used in eq 2.…”

“…Introducing the effective diameter Deff = D ( l + 6) (7) and the effective excluded volume (8) 4 we can write the free energy in the isotropic phase as beff = ZLZDeff…”

Evidence of the hexagonal columnar liquid-crystal phase of hard colloidal platelets by high-resolution SAXS

“…Onsager also showed that the particle shape alone is enough to induce such behaviour. Moreover, at a later stage, it was found that rodlike colloids show the nematic-to-smectic-A phase transition, as in the case of TMV [8,9], fd virus [10][11][12] and β-FeOOH [13]. A detailed a e-mail: h.n.w.lekkerkerker@chem.uu.nl description of this phase transition came with theory [14][15][16][17][18] and computer simulations [19,20], showing that hardcore interactions are enough to induce such ordering.…”

Gravity-induced liquid crystal phase transitions of colloidal platelets

“…In the 1950s, Oster 14 reported on an I-N biphasic suspension of tobacco mosaic virus rods that developed a third ͑Smectic-A) phase on the bottom of the sample after some time, an observation that was later confirmed by Kreibig and Wetter. 15 In neither case, a quantitative analysis was performed. Brian, Frisch, and Lerman 16 investigated sedimented suspensions of DNA-fragments at high salt concentration and analyzed their results in terms of a scaled particle theory equation of state.…”