7BA2

D319A mutant of the PilB minor pilin from Streptococcus sanguinis

Summary for 7BA2

• Entry DOI: 10.2210/pdb7ba2/pdb
• Related: 7B7P
• Descriptor: Type IV pilus biogenesis protein PilB (1 entity in total)
• Functional Keywords: type iv pili, pilin, von willebrand factor a-like domain, midas, cell adhesion
• Biological source: Streptococcus sanguinis
• Total number of polymer chains: 2
• Total formula weight: 94820.74

Authors

Pelicic, V.,Sheppard, D. (deposition date: 2020-12-15, release date: 2021-04-28, Last modification date: 2024-01-31)

Primary citation

Raynaud, C.,Sheppard, D.,Berry, J.L.,Gurung, I.,Pelicic, V.
PilB from Streptococcus sanguinis is a bimodular type IV pilin with a direct role in adhesion.
Proc.Natl.Acad.Sci.USA, 118:-, 2021

PubMed Abstract: Type IV pili (T4P) are functionally versatile filamentous nanomachines, nearly ubiquitous in prokaryotes. They are predominantly polymers of one major pilin but also contain minor pilins whose functions are often poorly defined and likely to be diverse. Here, we show that the minor pilin PilB from the T4P of displays an unusual bimodular three-dimensional structure with a bulky von Willebrand factor A-like (vWA) module "grafted" onto a small pilin module via a short loop. Structural modeling suggests that PilB is only compatible with a localization at the tip of T4P. By performing a detailed functional analysis, we found that 1) the vWA module contains a canonical metal ion-dependent adhesion site, preferentially binding Mg and Mn, 2) abolishing metal binding has no impact on the structure of PilB or piliation, 3) metal binding is important for T4P-mediated twitching motility and adhesion to eukaryotic cells, and 4) the vWA module shows an intrinsic binding ability to several host proteins. These findings reveal an elegant yet simple evolutionary tinkering strategy to increase T4P functional versatility by grafting a functional module onto a pilin for presentation by the filaments. This strategy appears to have been extensively used by bacteria, in which modular pilins are widespread and exhibit an astonishing variety of architectures.

PubMed: 34031252
DOI: 10.1073/pnas.2102092118

Experimental method

X-RAY DIFFRACTION (3 Å)