CRYO-ELECTRON MICROSCOPY RECONSTRUCTIONS OF THE PSEUDOMONAS AERUGINOSA AND NEISSERIA GONORRHOEAE TYPE IV PILI AT SUB-NANOMETER RESOLUTION

• Published in: Structure (London) Vol. 25; no. 9; pp. 1423 - 1435.e4
• Main Authors: Wang, Fengbin, Coureuil, Mathieu, Osinski, Tomasz, Orlova, Albina, Altindal, Tuba, Gesbert, Gaël, Nassif, Xavier, Egelman, Edward H., Craig, Lisa
• Format: Journal Article
• Language: English
• Published: 05.09.2017
• ISSN: 0969-2126; 1878-4186
• DOI: 10.1016/j.str.2017.07.016

We report here cryo-electron microscopy reconstructions of Type IV pili (T4P) from two important human pathogens, Pseudomonas aeruginosa and Neisseria gonorrhoeae , at ~ 8 Å and 5 Å resolution, respectively. The two structures reveal distinct arrangements of the pilin globular domains on the pilus surfaces, which impart different helical parameters, but similar packing of the conserved N-terminal α-helices, α1, in the filament core. In contrast to the continuous α-helix seen in the x-ray crystal structures of the P. aeruginosa and N. gonorrhoeae pilins, α1 in the pilus filaments has a melted segment located between conserved helix-breaking residues Gly14 and Pro22, as seen for the Neisseria meningitidis T4P. Using mutagenesis we show that Pro22 is critical for pilus assembly, as are Thr2 and Glu5, which are positioned to hydrogen bond in the hydrophobic filament core. These structures provide a framework for understanding T4P assembly, function and biophysical properties. Wang et al. report cryo-EM reconstructions of Type IV pili from P. aeruginosa and N. gonorrhoeae . These structures reveal that a melted portion of the pilin α-helical N-terminus is a common feature of Type IVa pili and is necessary for packing into the pilus filament.