title: A new topology of the HK97-like fold revealed in Bordetella bacteriophage by cryoEM at 3.5 A resolution.
abstract: Bacteriophage BPP-1 infects and kills Bordetella species that cause whooping cough. Its diversity-generating retroelement (DGR) provides a naturally occurring phage-display system, but engineering efforts are hampered without atomic structures. Here, we report a cryo electron microscopy structure of the BPP-1 head at 3.5 Å resolution. Our atomic model shows two of the three protein folds representing major viral lineages: jellyroll for its cement protein (CP) and HK97-like ('Johnson') for its major capsid protein (MCP). Strikingly, the fold topology of MCP is permuted non-circularly from the Johnson fold topology previously seen in viral and cellular proteins. We illustrate that the new topology is likely the only feasible alternative of the old topology. β-sheet augmentation and electrostatic interactions contribute to the formation of non-covalent chainmail in BPP-1, unlike covalent inter-protein linkages of the HK97 chainmail. Despite these complex interactions, the termini of both CP and MCP are ideally positioned for DGR-based phage-display engineering. DOI: http://dx.doi.org/10.7554/eLife.01299.001.
authors.affiliation: California NanoSystems Institute, University of California, Los Angeles, Los Angeles, United States.
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Huatao
authors.initials: H
authors.lastname: Guo
authors.forename: Lei
authors.initials: L
authors.lastname: Jin
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Czornyj
authors.forename: Asher
authors.initials: A
authors.lastname: Hodes
authors.forename: Wong H
authors.initials: WH
authors.lastname: Hui
authors.forename: Angela W
authors.initials: AW
authors.lastname: Nieh
authors.forename: Jeff F
authors.initials: JF
authors.lastname: Miller
authors.forename: Z Hong
authors.initials: ZH
authors.lastname: Zhou
mesh_terms: D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000737:chemistry / Q000648:ultrastructure*; D001884:Bordetella / Q000821:virology*; D020285:Cryoelectron Microscopy; D004591:Electrophoresis, Polyacrylamide Gel; D013058:Mass Spectrometry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D014764:Viral Proteins / Q000737:chemistry / Q000648:ultrastructure*
chemical_list: D014764:Viral Proteins
keywords: CryoEM; atomic resolution; fold topology; non-covalent chainmail; phage-display