- PDB-4jpp: Bacteriophage phiX174 H protein residues 143-282 -
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基本情報
登録情報
データベース: PDB / ID: 4jpp
タイトル
Bacteriophage phiX174 H protein residues 143-282
要素
Minor spike protein H
キーワード
VIRAL PROTEIN / helical barrel / tail tube / pilot DNA during phage infection
機能・相同性
Minor spike protein / Microvirus H protein (pilot protein) / lipopolysaccharide-mediated virion attachment to host cell / viral capsid / symbiont entry into host cell / identical protein binding / Minor spike protein H
ジャーナル: Nature / 年: 2014 タイトル: Icosahedral bacteriophage ΦX174 forms a tail for DNA transport during infection. 著者: Lei Sun / Lindsey N Young / Xinzheng Zhang / Sergei P Boudko / Andrei Fokine / Erica Zbornik / Aaron P Roznowski / Ian J Molineux / Michael G Rossmann / Bentley A Fane / 要旨: Prokaryotic viruses have evolved various mechanisms to transport their genomes across bacterial cell walls. Many bacteriophages use a tail to perform this function, whereas tail-less phages rely on ...Prokaryotic viruses have evolved various mechanisms to transport their genomes across bacterial cell walls. Many bacteriophages use a tail to perform this function, whereas tail-less phages rely on host organelles. However, the tail-less, icosahedral, single-stranded DNA ΦX174-like coliphages do not fall into these well-defined infection processes. For these phages, DNA delivery requires a DNA pilot protein. Here we show that the ΦX174 pilot protein H oligomerizes to form a tube whose function is most probably to deliver the DNA genome across the host's periplasmic space to the cytoplasm. The 2.4 Å resolution crystal structure of the in vitro assembled H protein's central domain consists of a 170 Å-long α-helical barrel. The tube is constructed of ten α-helices with their amino termini arrayed in a right-handed super-helical coiled-coil and their carboxy termini arrayed in a left-handed super-helical coiled-coil. Genetic and biochemical studies demonstrate that the tube is essential for infectivity but does not affect in vivo virus assembly. Cryo-electron tomograms show that tubes span the periplasmic space and are present while the genome is being delivered into the host cell's cytoplasm. Both ends of the H protein contain transmembrane domains, which anchor the assembled tubes into the inner and outer cell membranes. The central channel of the H-protein tube is lined with amide and guanidinium side chains. This may be a general property of viral DNA conduits and is likely to be critical for efficient genome translocation into the host.