Thermus bacteriophage P23-77 : key member of a novel, but ancient family of viruses from extreme environments

Crystallization and preliminary crystallographic analysis of the major capsid proteins VP16 and VP17 of bacteriophage P23-77.

The major capsid proteins VP16 and VP17 of bacteriophage P23-77 have been crystallized using both recombinant and purified virus and preliminary diffraction analyses have been performed.

A Unique Group of Virus-Related, Genome-Integrating Elements Found Solely in the Bacterial Family Thermaceae and the Archaeal Family Halobacteriaceae

ABSTRACT Viruses SH1 and P23-77, infecting archaeal Haloarcula species and bacterial Thermus species, respectively, were recently designated to form a novel viral lineage. In this study, the lineage is expanded to archaeal Halomicrobium and bacterial Meiothermus species by analysis of five genome-integrated elements that share the core genes with these viruses.

The Minor Capsid Protein VP11 of Thermophilic Bacteriophage P23-77 Facilitates Virus Assembly by Using Lipid-Protein Interactions

ABSTRACT Thermus thermophilus bacteriophage P23-77 is the type member of a new virus family of icosahedral, tailless, inner-membrane-containing double-stranded DNA (dsDNA) viruses infecting thermophilic bacteria and halophilic archaea. The viruses have a unique capsid architecture consisting of two major capsid proteins assembled in various building blocks. We analyzed the function of the minor capsid protein VP11, which is the third known capsid component in bacteriophage P23-77. Our findings show that VP11 is a dynamically elongated dimer with a predominantly α-helical secondary structure and high thermal stability. The high proportion of basic amino acids in the protein enables electrost…

Bacteriophage P23-77 capsid protein structures reveal the archetype of an ancient branch from a major virus lineage.

Summary It has proved difficult to classify viruses unless they are closely related since their rapid evolution hinders detection of remote evolutionary relationships in their genetic sequences. However, structure varies more slowly than sequence, allowing deeper evolutionary relationships to be detected. Bacteriophage P23-77 is an example of a newly identified viral lineage, with members inhabiting extreme environments. We have solved multiple crystal structures of the major capsid proteins VP16 and VP17 of bacteriophage P23-77. They fit the 14 Å resolution cryo-electron microscopy reconstruction of the entire virus exquisitely well, allowing us to propose a model for both the capsid archi…