Phage head

Murialdo, H., 1991. Bacteriophage lambda DNA maturation and packaging. Annual Review of Biochemistry 60 125-153. Review of the biochemi.stry of packaging DNA into A phage heads. 

FIG. 1 Monolayer of T7 phage heads. Cryoelectron micrograph of tailless mutant of T7 bacteriophage. Bar 50 nm. (From Ref. 42. Copyright 1997 Cell Press.)... 

Assembly and lysis In the case of T4, assembly of heads and tails occur on independent pathways. DNA is packaged into the assembled head and the tail and tail fibers are added subsequently. Somehow, the DNA is packed tightly and inserted into the empty phage head. 

Replicate. 1 Recover cloned DNA in replicated plasmid by using RE. Recover replicated DNA lysing E. coli. Clone in plasmid. 4 Recover. 4 Package into phage heads. 4 Clone in E. coli. 

PH (plekstrin homology) domain 102, 367, 566, 571 Phaeophyta 22 Phage head 363 Phage lambda... 

The main complication while selecting for high-affinity clones is avidity, which is caused by two or more copies of the antibody on the phage head... 

Fig. 2. Bacteriophage 029. On the right is shown a schematic of the mature bacteriophage 029, with the various limbs and devices it uses in effecting its life cycle. The phage head is fdled with DNA, and extends from one vertex the dodecameric connector structure and pRNA, at the top of the long tubular structure through which the viral genome is injected into the host.

Thirteen-fold symmetry was observed first in SPPl connectors (Dube et al, 1993). Apart from reports of 13-fold symmetry in 029 connectors (e.g., Dube et al, 1993), which are at odds with the 12-fold symmetry disclosed by high-resolution atomic force microscopy (AFM) analysis (Muller et al, 1997) and a crystal structure (Simpson et al, 2000), the T3/ T7 system is the only other one in which 13-fold has so far been observed. However, T3 and T7 also produce 12-fold connectors, and, significantly, only 12-fold symmetry was observed for connectors isolated from T3 capsids (Carazo et al, 1986 Donate et al, 1988). Pending experimental determination of the order (s) of symmetry of connectors in situ, the emerging picture (Valpuesta et al, 2000) is that connectors are 12-fold symmetric in phage heads, and 13-fold variants, when they occur, are probably an aberrant oligomerization product that results when overexpression overloads the normal biosynthetic assembly pathway within cells. 

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