Structure of the tubular variants of the head of bacteriophage T4 (Polyheads)

Yanagida, Mitsuhiro; DeRosier, David J.; Klug, A.

doi:10.1016/0022-2836(72)90203-3

Cited by 45 publications

(14 citation statements)

References 6 publications

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“…The filtration in Fig. 4c is comparable to the ones shown by Yanagida et al (19) of the "fine aged" and the "high temperature" polyheads which also show distinct (6+1) capsomers. We still have t o establish the significant difference between these capsomer morphologies and those of giants.…”

Section: Protein Composition Of the Capsidsupporting

confidence: 84%

“…Figure 2 shows a typical micrograph of (22-) polyheads, the diffraction pattern of a chosen length of polyhead, and the optically filtered image of one side. served (19) and which probably arise through post-lysis modifications of the "coarse empty" type. It is noteworthy that the 24-polyheads are the only tubular forms whose production is synchronous with that of 7-particles.…”

Section: Protein Composition Of the Capsidmentioning

confidence: 99%

“…a, and a, are the mean lengths of the lattice vectors, as measured for the five different mutations in question. The notation is that of Yanagida et al (19).…”

Section: Protein Composition Of the Capsidmentioning

confidence: 99%

“…We still have t o establish the significant difference between these capsomer morphologies and those of giants. It is of great interest that the lattice constants measured by Yanagida et al (19) for their "fine aged," "fine mottled," and "high temperature" categories of 22-polyheads are all in the vicinity of 125 A. In consequence their surface lattice would seem, in at least one important respect, t o bear a closer resemblance t o the lattices of the T4 giants (lattice constant 124 a) than t o that of the "coarse empty" polyhead ( I 12 a).…”

Section: Protein Composition Of the Capsidmentioning

confidence: 99%

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The transformation of τ particles into t4 heads. II. Transformations of the surface lattice an related observations on form determination

et al. 1974

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In part 1 of this paper ( I ) we give evidence that the P23-capsoid of 7-particles is transformed in situ i n t o the P23*-capsid of' normal phage. Using t h e polymorphism of phage T4, we have chosen polyheads as representative of P 2 3 assemblies and giant phages as representative of P23* assemblies in order t o study their surface crystals by optical filtration of micrographs. We found for polyheads a lattice constant of 1 I 2 a with the typical hexameric, ringlike capsomer and for t h e giants a lattice constant of 124 a with quite a different capsomer morphology, of t h e t y p e (h+l). From the stoichiometry of t h e proteins composing the normal capsid we conclude that the prototner is a single P23* molecule and that the minor capsidproteins must be in singular positions on t h e surface lattice o r on t h e polyhedral head (center of capsomers, vertices, o r basal part).We extrapolate the findings on the giant head to t h e normal head and give a geometric model which is consistent with 1 , I 00 molecules o f P23* per capsid.We discuss t h e part of form inheritance contrihuted by P23 and t h e other formgiving gene products and give evidence that morphologic characters are t h e result of pairs of a reaction chain of interacting gene products. The example we give is the giant head produced by a t s mutant in gene 2 4 at 3h'C.

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Section: Protein Composition Of the Capsidsupporting

confidence: 84%

Section: Protein Composition Of the Capsidmentioning

confidence: 99%

“…a, and a, are the mean lengths of the lattice vectors, as measured for the five different mutations in question. The notation is that of Yanagida et al (19).…”

Section: Protein Composition Of the Capsidmentioning

confidence: 99%

Section: Protein Composition Of the Capsidmentioning

confidence: 99%

See 2 more Smart Citations

The transformation of τ particles into t4 heads. II. Transformations of the surface lattice an related observations on form determination

et al. 1974

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“…These polyheads have the diameter of the innermost layer of the multilayered polyheads observed in 22 defective cells (22). The shell of the polyhead is composed of subunits (mostly P23) arranged on a hexagonal net which has been studied in detail by electron microscopy and optical diffraction (30)(31)(32)(33).…”

Section: Nt Rod U Ct I0 N Genes Involved In the Early Assembly Stepmentioning

confidence: 99%

Maturation of the head of bacteriophage T4. V. A possible DNA packaging mechanism: In vitro cleavage of the head proteins and the structure of the core of the polyhead

1974

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The most recent developments in studies on the maturation of the head of bacteriophage T4 are described and discussed.The The P22 core proteins appear t o be the precursors of the well-known, highly acidic internal peptides. We have tested the idea that these internal peptides collapse D N A by a repulsive interaction as various polymers like polyethylene oxide (PeO) and polyacrylate(PAA) do. We found that high concentrations of the internal peptides, polyaspartic acid, and polyglutamic acid, collapse DNA. This supports the idea that repulsive interactions with the internal peptides may collapse the DNA inside the head, and thus pull the DNA in.The structure of the D N A collapsed by PeO was studied with the electron microscope and contrasted with the structure of D N A collapsed by polylysine. We find PeO collapses T4 D N A into compact particles best described as a ball of string, of about the size of the T 4 head. Two structures are seen in preparations of polylysinecollapsed DNA. One has the shape of a donut and the DNA strand appears t o be radially distributed as a spiral; the other is a stemlike structure in which the D N A is folded back and forth in a pleated structure. 2760 1974 Alan R.

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Kinetics of proflavin binding to bacteriophages T2L and T4D

McCall

Bloomfield

1976

Biopolymers

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SynopsisWe have measured the kinetics of proflavin binding to T-even bacteriophages-the 700 S and 1000 S forms of T2L, T4D, and T4D os41-by difference spectroscopy a t 430 nm.Measurements were carried out from 2 2 O to 37°C. Binding is very slow to encapsulated DNA compared to free DNA, requiring hours to reach equilibrium. The kinetic data are compatible with the two-step mechanismwhere P is proflavin, N is nucleotide, and PN, and PN2 are complexes. Computer integration of the rate equations allows evaluation of the rate constants; previous equilibrium measurements gave thermodynamic parameters. For all phage studied, the bimolecular step is endothermic with high positive entropy; the second, unimolecular step is highly exothermic with small negative entropy change. Both forms of T2L bind proflavin with essentially the same rate, as do T4D and the osmotic shock resistant mutant T4D os41. This suggests that the encapsulated DNA is equally accessible to proflavin in both forms of each phage. However, T4D binds dye appreciably faster than TZL, indicating that capsid permeability or DNA environment (glucosylation or packing) is different in the two species.

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Structure of the tubular variants of the head of bacteriophage T4 (Polyheads)

Cited by 45 publications

References 6 publications

The transformation of τ particles into t4 heads. II. Transformations of the surface lattice an related observations on form determination

The transformation of τ particles into t4 heads. II. Transformations of the surface lattice an related observations on form determination

Maturation of the head of bacteriophage T4. V. A possible DNA packaging mechanism: In vitro cleavage of the head proteins and the structure of the core of the polyhead

Kinetics of proflavin binding to bacteriophages T2L and T4D

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