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Hydrodynamic properties and structure of fd virus

1977; Elsevier BV; Volume: 116; Issue: 3 Linguagem: Inglês

10.1016/0022-2836(77)90086-9

1089-8638

Jay Newman, Harry L. Swinney, Loren A. Day,

Evolution and Genetic Dynamics

A length of 8950 ± 200 Å and a diameter of 90 ± 10 Å have been obtained for fd virus from a simultaneous solution of the Broersma equations relating the length and diameter of a rod-like particle to its rotational, DR, and translational, DT, diffusion coefficients. Measurements of DR were by transient electric birefringence, and of DT by low-angle intensity fluctuation spectroscopy. A mass of (16.4 ± 0.6) × 106 daltons was calculated from the Svedberg equation using our measured values of DT, the sedimentation coefficient and the density increment. These results, together with the molecular weight of fd DNA, give a total number of major coat protein subunits of 2710 ± 110 and a ratio of nucleotides to protein subunits which is definitely non-integral, 2.30 ± 0.11. These measurements help delineate significant structural differences between fd and other filamentous viruses. Also included in this paper is an Appendix (by L. A. Day & S. A. Berkowitz) concerning the number of nucleotides, 6370 ± 140, and the density and refractive index increments of fd DNA.