title: Domain-swap polymerization drives the self-assembly of the bacterial flagellar motor.
abstract: Large protein complexes assemble spontaneously, yet their subunits do not prematurely form unwanted aggregates. This paradox is epitomized in the bacterial flagellar motor, a sophisticated rotary motor and sensory switch consisting of hundreds of subunits. Here we demonstrate that Escherichia coli FliG, one of the earliest-assembling flagellar motor proteins, forms ordered ring structures via domain-swap polymerization, which in other proteins has been associated with uncontrolled and deleterious protein aggregation. Solution structural data, in combination with in vivo biochemical cross-linking experiments and evolutionary covariance analysis, revealed that FliG exists predominantly as a monomer in solution but only as domain-swapped polymers in assembled flagellar motors. We propose a general structural and thermodynamic model for self-assembly, in which a structural template controls assembly and shapes polymer formation into rings.
authors: Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.|European Molecular Biology Laboratory Australia Node for Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
authors: Matthew A B
authors: MA
authors: Baker
authors: Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.
authors: Robert M G
authors: RM
authors: Hynson
authors: Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.
authors: Lorraine A
authors: LA
authors: Ganuelas
authors: Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.
authors: Nasim Shah
authors: NS
authors: Mohammadi
authors: Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.
authors: Chu Wai
authors: CW
authors: Liew
authors: Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.
authors: Anthony A
authors: AA
authors: Rey
authors: Australian Nuclear and Science Technology Organisation, Lucas Heights, New South Wales, Australia.
authors: Anthony P
authors: AP
authors: Duff
authors: Australian Nuclear and Science Technology Organisation, Lucas Heights, New South Wales, Australia.
authors: Andrew E
authors: http://orcid.org/0000-0001-8856-3120
authors: AE
authors: Whitten
authors: Australian Nuclear and Science Technology Organisation, Lucas Heights, New South Wales, Australia.
authors: Cy M
authors: http://orcid.org/0000-0002-8718-7343
authors: CM
authors: Jeffries
authors: Department of Biochemistry, Oxford University, Oxford, UK.
authors: Nicolas J
authors: NJ
authors: Delalez
authors: Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
authors: Yusuke V
authors: YV
authors: Morimoto
authors: Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.
authors: Daniela
authors: D
authors: Stock
authors: Department of Biochemistry, Oxford University, Oxford, UK.
authors: Judith P
authors: JP
authors: Armitage
authors: Department of Physics, Oxford University, Oxford, UK.
authors: Andrew J
authors: AJ
authors: Turberfield
authors: Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
authors: Keiichi
authors: K
authors: Namba
authors: Department of Physics, Oxford University, Oxford, UK.
authors: Richard M
authors: RM
authors: Berry
authors: Structural and Computational Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia.|European Molecular Biology Laboratory Australia Node for Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
authors: Lawrence K
authors: LK
authors: Lee
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000737:chemistry*; D005407:Flagella / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D008956:Models, Chemical; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry / Q000378:metabolism*; D001678:Organelle Biogenesis; D011487:Protein Conformation; D055503:Protein Multimerization
chemical_list: D001426:Bacterial Proteins; C075660:Flig protein, Bacteria; D046911:Macromolecular Substances; D020409:Molecular Motor Proteins