Assembly of Bacteriophage PRD1 Spike Complex:  Role of the Multidomain Protein P5

Abstract

The spike structure of bacteriophage PRD1 is comprised of proteins P2, P5, and P31. It resembles the corresponding receptor-binding structure of adenoviruses. We show that purified recombinant protein P5 is an elongated (30 x 2.7 nm; R(h) = 5.5 nm), multidomain trimer which can slowly associate into nonamers. Cleavage of the 340 amino acid long P5 with collagenase yields 2 fragments. The larger, 205 amino acid long C-terminal fragment appears to contain the residues responsible for the trimerization of the protein, whereas the smaller N-terminal part mediates the interaction of P5 with the pentameric vertex protein P31 (24 x 2.5 nm, R(h) = 4.2 nm). In addition, the presence of the N-terminal sequence is required for the formation of the P5 nonamer. The results presented here suggest that P5 and P31 form an elongated adaptor complex at the 5-fold vertexes of the virion which anchors the adsorption protein P2 (21 x 2.5 nm; R(h) = 4.1 nm). Our results also suggest that the P5 trimer forms a substantial part of the viral spike shaft that was previously thought to be composed exclusively of protein P2.

The Two ADF-H Domains of Twinfilin Play Functionally Distinct Roles in Interactions with Actin Monomers

“…The formed complexes were then characterized by gel filtration chromatography (Superdex-200 column, Pharmacia) coupled with a light scattering detector (Precision Detectors, Franklin, MA) as described previously (Caldentey et al, 2000). The apparent masses of the eluted complexes were calculated using calibration with monomeric actin and the manufacturer's software.…”

Tale of two spikes in bacteriophage PRD1

“…1B 1a and 1b) considers the following: On the basis of incorporation of shortened P5 fragments into the virion, it has been proposed that ''the trimeric P5 is associated with the pentameric P31'' and ''P2 is the most distal component of the spike structure connected to P5'' (20). These data were supported by a parallel study on the hydrodynamic radii of the vertex proteins and their complexes (19). Fig.…”

“…P5 is a trimer in the crystal structure and consists of two major domains, the ␤-barrel C-terminal head with a tumor necrosis factor-like fold and an N-terminal base domain. They are separated by a linker region that consists of a collagen-like region (Gly-124 through Gly-140), a shaft with a ␤-spiral fold (Thr-141 through , and the eight-glycine stretch (Gly-191 through Gly-198) (14,19). The low-resolution SAXS models of the full-length P5 and the collagenase-resistant fragment complement the x-ray structure (28).…”

“…Protein P2 is a monomeric receptor-binding protein (4,17,18). P5, designated as the spike protein, is released as a soluble trimer from the virion (19). A virus mutant deficient in pentameric vertex protein P31 lacks both proteins P2 and P5 (3).…”

“…Fig. 1B model 1a assumes that the P5 N-terminal domain is embedded in the capsid by forming a heteropentameric base with P31 (19,28), which is an assumption mainly based on the sequence similarity between the P5 N-terminal fragment and P31 [supporting information (SI) Fig. 6].…”