Structure of the bacterial sex F pilus reveals an assembly of a stoichiometric protein-phospholipid complex

• Tiago R.D. Costa ^[1] ; Aravindan Ilangovan ; Marta Ukleja ^[1]
  1. [1] University College London

     University College London

     Reino Unido

     
• Localización: Cell, ISSN 0092-8674, Vol. 166, Nº. 6, 2016, págs. 1436-1444
• Idioma: inglés
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• Resumen

  • Conjugative pili are widespread bacterial appendages that play important roles in horizontal gene transfer, in spread of antibiotic resistance genes, and as sites of phage attachment. Among conjugative pili, the F “sex” pilus encoded by the F plasmid is the best functionally characterized, and it is also historically the most important, as the discovery of F-plasmid-mediated conjugation ushered in the era of molecular biology and genetics. Yet, its structure is unknown. Here, we present atomic models of two F family pili, the F and pED208 pili, generated from cryoelectron microscopy reconstructions at 5.0 and 3.6 Å resolution, respectively. These structures reveal that conjugative pili are assemblies of stoichiometric protein-phospholipid units. We further demonstrate that each pilus type binds preferentially to particular phospholipids. These structures provide the molecular basis for F pilus assembly and also shed light on the remarkable properties of conjugative pili in bacterial secretion and phage infection.