1. Structure of a Bacterial Virus DNA-Injection Protein Complex Reveals a Decameric Assembly with a Constricted Molecular Channel
- Author
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Tsutomu Matsui, Jeffrey A. Speir, Thomas M. Weiss, Lingfei Liang, Haiyan Zhao, Brittany Varnado, Anna Y. Lynn, Liang Tang, and Zihan Lin
- Subjects
Models, Molecular ,0301 basic medicine ,Phagemid ,Cell Membranes ,lcsh:Medicine ,Biochemistry ,Negative Staining ,Viral Packaging ,Bacteriophage ,chemistry.chemical_compound ,Protein structure ,Macromolecular Structure Analysis ,Bacteriophages ,lcsh:Science ,Staining ,Multidisciplinary ,Molecular Structure ,biology ,Physics ,Solutions ,Nucleic acids ,Chemistry ,Viruses ,Physical Sciences ,Host cell envelope ,Cellular Structures and Organelles ,Cell envelope ,Research Article ,Protein Structure ,Research and Analysis Methods ,Microbiology ,Viral Proteins ,03 medical and health sciences ,Imaging, Three-Dimensional ,Virology ,Genetics ,Molecular Biology ,Chemical Physics ,Host Cells ,lcsh:R ,Organisms ,Biology and Life Sciences ,Proteins ,DNA structure ,Cell Biology ,DNA ,biology.organism_classification ,Molecular biology ,Viral Replication ,Protein Structure, Tertiary ,030104 developmental biology ,chemistry ,Specimen Preparation and Treatment ,Cytoplasm ,DNA, Viral ,Biophysics ,lcsh:Q ,Protein Multimerization ,Bacterial virus ,Viral Transmission and Infection - Abstract
The multi-layered cell envelope structure of Gram-negative bacteria represents significant physical and chemical barriers for short-tailed phages to inject phage DNA into the host cytoplasm. Here we show that a DNA-injection protein of bacteriophage Sf6, gp12, forms a 465-kDa, decameric assembly in vitro. The electron microscopic structure of the gp12 assembly shows a ~150-Å, mushroom-like architecture consisting of a crown domain and a tube-like domain, which embraces a 25-Å-wide channel that could precisely accommodate dsDNA. The constricted channel suggests that gp12 mediates rapid, uni-directional injection of phage DNA into host cells by providing a molecular conduit for DNA translocation. The assembly exhibits a 10-fold symmetry, which may be a common feature among DNA-injection proteins of P22-like phages and may suggest a symmetry mismatch with respect to the 6-fold symmetric phage tail. The gp12 monomer is highly flexible in solution, supporting a mechanism for translocation of the protein through the conduit of the phage tail toward the host cell envelope, where it assembles into a DNA-injection device.
- Published
- 2016