Structure of T-2 Bacteriophage

Kilkson, Rein; Maestre, Marcos F.

doi:10.1038/195494a0

Cited by 34 publications

(7 citation statements)

References 9 publications

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“…imilarly if E = E,k then E, = (n * E)n = E,k El = (n X E) X n = (Elk X k) X k = 0 (13) P = aL'Ek = aL'E (14) Equation (14)…”

Section: Iel -+4rsmentioning

confidence: 99%

Intrinsic Birefringence of Multiple-Coiled DNA, Theory and Applications

Maestre¹,

Kilkson²

1965

Biophysical Journal

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The intrinsic birefringence of multiple-coiled DNA is computed in terms of an equally dense array of parallel DNA molecules. The birefringence for n times-coiled DNA molecules is given by [Formula: see text] where beta(o) = 0, beta(i) = tan(-1) (p(i)/2pir(i)), p(i) = period of the i(th) helix coil and r(i) = radius of i(th) helix coil. The formula is applied to two cases of helically coiled DNA in biological material and found to agree quantitatively with experimental results.

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“…imilarly if E = E,k then E, = (n * E)n = E,k El = (n X E) X n = (Elk X k) X k = 0 (13) P = aL'Ek = aL'E (14) Equation (14)…”

Section: Iel -+4rsmentioning

confidence: 99%

Intrinsic Birefringence of Multiple-Coiled DNA, Theory and Applications

Maestre¹,

Kilkson²

1965

Biophysical Journal

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“…The physical description of the ordered packing of the ds-DNA inside the bacteriophage capsid is usually captured in one of the variants of the inverse spool model first invoked in the study of the T2 bacteriophage [139][140][141] and formalized by Grosberg et al 142 . The inverse spool model has been subsequently refined by Odijk and Gelbart and coworkers [143][144][145][146][147][148][149][150] and is based on the decomposition of the dsDNA total energy within the viral capsid into an interaction term and a bending term which leads to a reasonable description of the genome ejection process 151,152 .…”

Section: Energies Of Bacteriophagesmentioning

confidence: 99%

Energies and pressures in viruses: contribution of nonspecific electrostatic interactions

Šiber

Božič

Podgornik

2012

Phys. Chem. Chem. Phys.

132

153

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We summarize some aspects of electrostatic interactions in the context of viruses. A simplified but, within well defined limitations, reliable approach is used to derive expressions for electrostatic energies and the corresponding osmotic pressures in single-stranded RNA viruses and double-stranded DNA bacteriophages. The two types of viruses differ crucially in the spatial distribution of their genome charge which leads to essential differences in their free energies, depending on the capsid size and total charge in a quite different fashion. Differences in the free energies are trailed by the corresponding characteristics and variations in the osmotic pressure between the inside of the virus and the external bathing solution.

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“…A large number ofDNA molecules have been shown to exist in a supercoiled form (Vinograd & Lebowitz, 1966) and it seems likely that most others do also. In addition supercoiled, but not necessarily circular, DNA has been invoked as a virus-packaging method (Kilkson & Maestre, 1962), as structural (Pardon et al, 1967;Luzzati & Nicolaieff, 1963) and as functional (Crick, 1971) units in terms of gene regulation in chromosomes of higher cells.…”

mentioning

confidence: 99%

Light-scattering studies on supercoil unwinding

Campbell

Jolly

1973

Biochemical Journal

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It has been shown previously that supercoiled [unk]X174 bacteriophage intracellular DNA (mol.wt. 3.2x10(6)) with superhelix density, sigma=-0.025 (-12 superhelical turns) at 25 degrees C is best represented as a Y shape. In this work two techniques have been used to unwind the supercoil and study the changes in tertiary structure which result from changes in the secondary structure. The molecular weights from all experiments were in the range 3.2x10(6)+/-0.12x10(6). In experiments involving temperature change little change in the Y shape was observed between sigma=-0.027 (-13 superhelical turns, 14.9 degrees C) and sigma=-0.021 (-10 superhelical turns, 53.4 degrees C) as evidenced by the root-mean-square radius and the particle-scattering factor P(theta). However, at sigma=-0.0176 (-8 superhelical turns, 74.5 degrees C) the root-mean-square radius fell to between 60 and 70nm from 90nm indicating a large structural change, as did alterations in the P(theta) function. In experiments with the intercalating dye proflavine from values of bound proflavine of 0-0.06mol of dye/mol equiv. of nucleotide which correspond to values of sigma from -0.025 to -0.0004 (-12 to 0 superhelical turns) a similar transition was found when the superhelix density was changed by the same amount, and the molecule was shown to go through a further structural change as the unwinding of the duplex proceeded. At sigma=-0.018 (-9 superhelical turns) the structure was compatible with a toroid, and at sigma=-0.0004 it was compatible with a circle but at no point in the sequence of structure transitions was the structure compatible with the conventional straight interwound model normally visualized as the shape of supercoiled DNA.

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Structure of T-2 Bacteriophage

Cited by 34 publications

References 9 publications

Intrinsic Birefringence of Multiple-Coiled DNA, Theory and Applications

Intrinsic Birefringence of Multiple-Coiled DNA, Theory and Applications

Energies and pressures in viruses: contribution of nonspecific electrostatic interactions

Light-scattering studies on supercoil unwinding

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