Self-assembly of brome mosaic virus protein into capsids: Initial and final states of aggregation

doi:10.1016/0022-2836(83)90052-9

Journal of Molecular Biology

Volume 164, Issue 4, 15 March 1983, Pages 589-603

https://doi.org/10.1016/0022-2836(83)90052-9 Get rights and content

Abstract

The pH and ionic strength dependence of the states of aggregation of brome mosaic virus protein has been investigated by small angle neutron scattering, quasielastic light-scattering, analytical centrifugation and electron microscopy. At pH above neutrality, protein oligomers are found in dynamical equilibrium, comprising monomers, dimers and aggregates of higher molecular weight. By lowering the pH. capsids assemble spontaneously with dimensions in solution which depend on ionic strength. If formed by dialysis, they contain 180 monomers, but are 30 Å larger in diameter than the native virus. If formed by pH-jump, they contain less monomers; the deficiency decreases with decreasing the final pH and the initial protein concentration. Upon dehydration for electron microscopy, capsids contract by 10%.

References (36)

K.W. Adolph et al.
J. Mol. Biol
(1974)
K.W. Adolph et al.
J. Mol. Biol
(1977)
J.B. Bancroft et al.
Virology
(1967)
L.E. Bockstahler et al.
Biophys. J
(1962)
C. Chauvin et al.
Virology
(1978)
M. Cuillel et al.
J. Mol. Biol
(1983)
S. Cusack et al.
J. Mol. Biol
(1981)
W.C. Earnshaw et al.
J. Mol. Biol
(1978)
L. Hirth et al.
Advan. Virus Res
(1981)
B. Jacrot
J. Mol. Biol
(1975)

L.C. Lane

Advan. Virus Res

(1974)

P. Pfeiffer et al.

Virology

(1974)

D. Schneider et al.

J. Mol. Biol

(1978)

J.D. Stubbs et al.

J. Mol. Biol

(1964)

H. Yamazaki et al.

J. Mol. Biol

(1963)

M. Zulauf

J. Mol. Biol

(1977)

K.W. Adolph et al.

Nature (London)

(1975)

J.B. Bancroft

Advan. Virus Res

(1970)

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The stability of bromegrass mosaic virus (BMV) and empty shells reassembled in vitro from purified BMV coat protein was investigated under hydrostatic pressure, using solution small-angle neutron scattering. This technique allowed us to monitor directly the dissociation of the particles, and to detect conformational changes preceding dissociation. Significant dissociation rates were observed only if virions swelled upon increase of pressure, and pressure effects became irreversible at very high-pressure in such conditions. At pH 5.0, in buffers containing 0.5 M NaCl and 5 mM MgCl₂, BMV remained compact (radius 12.9 nm), dissociation was limited to ≈10% at 200 MPa, and pressure effects were totally reversible. At pH 5.9, BMV particles were slightly swollen under normal pressure and swelling increased with pressure. The dissociation was reversible to 90% for pressures up to 160 MPa, where its rate reached 28%, but became totally irreversible at 200 MPa. Pressure-induced swelling and dissociation increased further at pH 7.3, but were essentially irreversible. The presence of ²H₂O in the buffer strongly stabilized BMV against pressure effects at pH 5.9, but not at pH 7.3. Furthermore, the reversible changes of the scattered intensity observed at pH 5.0 and 5.9 provide evidence that pressure could induce the release of coat protein subunits, or small aggregates of these subunits from the virions, and that the dissociated components reassociated again upon return to low pressure. Empty shells were stable at pH 5.0, at pressures up to 260 MPa. They became ill-shaped at high-pressure, however, and precipitated slowly after return to normal conditions, providing the first example of a pressure-induced conformational drift in an assembled system.
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^†: Attachee de recherche at the Institut National de la Sante et de la Recherche Medicale (INSERM), France.

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Journal of Molecular Biology

Self-assembly of brome mosaic virus protein into capsids: Initial and final states of aggregation

Abstract

J. Mol. Biol

J. Mol. Biol

Virology

Biophys. J

Virology

J. Mol. Biol

J. Mol. Biol

J. Mol. Biol

Advan. Virus Res

J. Mol. Biol

Advan. Virus Res

Virology

J. Mol. Biol

J. Mol. Biol

J. Mol. Biol

J. Mol. Biol

Nature (London)

Advan. Virus Res