PilB from Streptococcus sanguinis is a bimodular type IV pilin with a direct role in adhesion.
Proc Natl Acad Sci U S A
; 118(22)2021 06 01.
Article
en En
| MEDLINE
| ID: mdl-34031252
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 Streptococcus sanguinis 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 Mg2+ and Mn2+, 2) abolishing metal binding has no impact on the structure of PilB or piliation, 3) metal binding is important for S. sanguinis 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.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oxidorreductasas
/
Streptococcus sanguis
/
Proteínas Bacterianas
/
Adhesión Celular
/
Proteínas Fimbrias
Tipo de estudio:
Prognostic_studies
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
2021
Tipo del documento:
Article
País de afiliación:
Reino Unido
Pais de publicación:
Estados Unidos