Polypeptide Composition of Poliovirions, Naturally Occurring Empty Capsids, and 14 S Precursor Particles

Abstract

The three serotypes of poliovirus were compared with respect to their polypeptide composition. Type 1, 2, and 3 strains were clearly different from each other in the electrophoretic mobilities of their larger structural polypeptides. Some of the viral polypeptides formerly identified as single peaks (e.g., VP 2) were shown to contain multiple components, indicating that purified virions contain at least six polypeptides. Three type 1 strains were indistinguishable in their viral polypeptides. A quantitative estimate was made of the polypeptide composition of the type 1 Mahoney poliovirion, as well as of naturally occurring empty capsids and 14S precursor particles. The data are discussed in light of the antigenic differences among polioviruses and the possible modes of virion morphogenesis.

Resolution of the major poliovirus capsid polypeptides into doublets

“…Reelution of the column using the same buffer supplemented with 0.5 M NaCl yielded a mixture of virions and empty particles from which the latter were purified as the 80 S peak in a 15 to 30% sucrose gradient. These empty particles were found by the normal electrophoresis to contain VPO, VPl, and VP3 but no VP2 or VP4, which is in agreement with the known composition of procapsids (Maize1 et al, 1967;Phillips and Fennell, 1973). The components resolved by pH gradient electrophoresis were VPO, Cl, C2, and a C5-C6 group (Fig.…”

“…If so, they must differ slightly in charge, molecular weight, or both. Such differences may conceivably originate in the accumulation of mutants as a result of serial passages (Phillips and Fennell, 1973). To prevent any such accumulation, however, each virus population examined in this work was grown from a single plaque by only four passages, and a mutational origin of the observed multiplicity can therefore be excluded.…”

Purification of Theiler's Murine Encephalomyelitis Virus and Analysis of the Structural Virion Polypeptides: Correlation of the Polypeptide Profile with Virulence

“…Two earlier reports in the literature contained information on polioviruses suggesting that the virion polypeptides might differ between wild and attenuated strains (1,14). Recently, Milstien et al 13were able to correlate a change in the polypeptide gel pattern with a decrease in neurovirulence of poliovirus type 1.…”

Role and mechanism of the maturation cleavage of VP0 in poliovirus assembly: Structure of the empty capsid assembly intermediate at 2.9 Å resolution

“…A number of intermediates accumulate to significant levels in the course of poliovirus assembly. These include the protomer consisting of P1; a cleaved protomer containing 1 copy each of VPO, VPl, and VP3; the pentamer, consisting of 5 copies each of VPO, VP3, and VP1 (Watanabe et al, 1965;Phillips & Fennel, 1973); the empty capsid, consisting of 60 copies each of VPO, VP3, and VPl (12 pentamers) (Jacobson & Baltimore, 1968a); and the mature virion, consisting of 60 copies each of VPl, VP2, VP3, and VP4 and the viral RNA. Some early studies have reported an additional intermediate termed the provirion, consisting of 60 copies each of VPO, VPl, and VP3, and 1 copy of the viral RNA (Fernandez-Tomas & Baltimore, 1973;Guttman & Baltimore, 1977).…”