Capsids and Genomes of Jumbo-Sized Bacteriophages Reveal the Evolutionary Reach of the HK97 Fold.

ABSTRACT: Large icosahedral viruses that infect bacteria represent an extreme of the coevolution of capsids and the genomes they accommodate. One subset of these large viruses is the jumbophages, tailed phages with double-stranded DNA genomes of at least 200,000 bp. We explored the mechanism leading to increased capsid and genome sizes by characterizing structures of several jumbophage capsids and the DNA packaged within them. Capsid structures determined for six jumbophages were consistent with the canonical phage HK97 fold, and three had capsid geometries with novel triangulation numbers (T=25, T=28, and T=52). Packaged DNA (chromosome) sizes were larger than the genome sizes, indicating that all jumbophages use a head-full DNA packaging mechanism. For two phages (PAU and G), the sizes appeared ve

SUBMITTER: Hua J 

PROVIDER: S-EPMC5646251 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature