%0 Journal Article
%T Structure and assembly of bacteriophage T4 head
%A Venigalla B Rao
%A Lindsay W Black
%J Virology Journal
%D 2010
%I BioMed Central
%R 10.1186/1743-422x-7-356
%X The T4-type bacteriophages are ubiquitously distributed in nature and occupy environmental niches ranging from mammalian gut to soil, sewage, and oceans. More than 130 such viruses that show similar morphological features as phage T4 have been described; from the T4 superfamily ~1400 major capsid protein sequences have been correlated to its 3D structure [1-3]. The features include large elongated (prolate) head, contractile tail, and a complex baseplate with six long, kinked tail fibers radially emanating from it. Phage T4 historically has served as an excellent model to elucidate the mechanisms of head assembly of not only T-even phages but of large icosahedral viruses in general, including the widely distributed eukaryotic viruses such as the herpes viruses. This review will focus on the advances in the past twenty years on the basic understanding of phage T4 head structure and assembly and the mechanism of DNA packaging. Application of some of this knowledge to develop phage T4 as a surface display and vaccine platform will also be discussed. The reader is referred to the comprehensive review by Black et al [4], for the early work on T4 head assembly.The overall architecture of the phage T4 head determined earlier by negative stain electron microscopy of the procapsid, capsid, and polyhead, including the positions of the dispensable Hoc and Soc proteins, has basically not changed as a result of cryo-electron microscopic structure determination of isometric capsids [5]. However, the dimensions of the phage T4 capsid and its inferred protein copy numbers have been slightly altered on the basis of the higher resolution cryo-electron microscopy structure. The width and length of the elongated prolate icosahedron [5] are Tend = 13 laevo and Tmid = 20 (86 nm wide and 120 nm long), and the copy numbers of gp23, Hoc and Soc are 960, 155, and 870, respectively (Figure 1).The most significant advance was the crystal structure of the vertex protein, gp24, and by inference
%U http://www.virologyj.com/content/7/1/356