title: The phage lambda major tail protein structure reveals a common evolution for long-tailed phages and the type VI bacterial secretion system.
abstract: Most bacteriophages possess long tails, which serve as the conduit for genome delivery. We report the solution structure of the N-terminal domain of gpV, the protein comprising the major portion of the noncontractile phage lambda tail tube. This structure is very similar to a previously solved tail tube protein from a contractile-tailed phage, providing the first direct evidence of an evolutionary connection between these 2 distinct types of phage tails. A remarkable structural similarity is also seen to Hcp1, a component of the bacterial type VI secretion system. The hexameric structure of Hcp1 and its ability to form long tubes are strikingly reminiscent of gpV when it is polymerized into a tail tube. These data coupled with other similarities between phage and type VI secretion proteins support an evolutionary relationship between these systems. Using Hcp1 as a model, we propose a polymerization mechanism for gpV involving several disorder-to-order transitions.
authors.affiliation: Department of Biochemistry, University of Toronto, Medical Sciences Building, Toronto, ON M5S 1A8, Canada.
authors.forename: Lisa G
authors.initials: LG
authors.lastname: Pell
authors.forename: Voula
authors.initials: V
authors.lastname: Kanelis
authors.forename: Logan W
authors.initials: LW
authors.lastname: Donaldson
authors.forename: P Lynne
authors.initials: PL
authors.lastname: Howell
authors.forename: Alan R
authors.initials: AR
authors.lastname: Davidson
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D010582:Bacteriophage lambda / Q000737:chemistry*; D005075:Biological Evolution; D017899:Caudovirales / Q000737:chemistry*; D006090:Gram-Negative Bacteria / Q000472:pathogenicity*; D026901:Membrane Transport Proteins / Q000737:chemistry*; D011487:Protein Conformation; D040681:Structural Homology, Protein; D014764:Viral Proteins / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D014764:Viral Proteins