Global biochemical and structural analysis of the type IV pilus from the Gram-positive bacterium Streptococcus sanguinis
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Type IV pili (Tfp) are functionally versatile filaments, widespread in prokaryotes, that belong to a large class of filamentous nanomachines known as type IV filaments (Tff). Although Tfp have been extensively studied in several Gram-negative pathogens where they function as key virulence factors, many aspects of their biology remain poorly understood. Here, we performed a global biochemical and structural analysis of Tfp in a recently emerged Gram-positive model, Streptococcus sanguinis. In particular, we focused on the five pilins and pilin-like proteins involved in Tfp biology in S. sanguinis. We found that the two major pilins, PilE1 and PilE2, (i) follow widely conserved principles for processing by the prepilin peptidase PilD and for assembly into filaments; (ii) display only one of the post-translational modifications frequently found in pilins, i.e. a methylated N-terminus; (iii) are found in the same hetero-polymeric filaments; and (iv) are not functionally equivalent. The 3D structure of PilE1, solved by NMR, revealed a classical pilin fold with a highly unusual flexible C-terminus. Intriguingly, PilE1 more closely resembles pseudopilins forming shorter Tff than bona fide Tfp-forming major pilins, underlining the evolutionary relatedness among different Tff. Finally, we show that S. sanguinis Tfp contain a low abundance of three additional proteins processed by PilD, the minor pilins PilA, PilB, and PilC. These findings provide the first global biochemical and structural picture of a Gram-positive Tfp and have fundamental implications for our understanding of a widespread class of filamentous nanomachines.
Date Issued
2019-04-26
Date Acceptance
2019-03-05
Citation
Journal of Biological Chemistry, 2019, 294, pp.6796-6808
ISSN
0021-9258
Publisher
American Society for Biochemistry and Molecular Biology
Start Page
6796
End Page
6808
Journal / Book Title
Journal of Biological Chemistry
Volume
294
Copyright Statement
© 2019 Berry et al. Published by The American Society for Biochemistry and Molecular Biology, Inc.
Author's Choice—Final version open access under the terms of the Creative Commons CC-BY license (https://creativecommons.org/licenses/by/4.0/)
Author's Choice—Final version open access under the terms of the Creative Commons CC-BY license (https://creativecommons.org/licenses/by/4.0/)
Sponsor
Medical Research Council (MRC)
Medical Research Council (MRC)
Medical Research Council (MRC)
Grant Number
MR/J006874/1B
MR/L008404/1
MR/P022197/1
Subjects
Science & Technology
Life Sciences & Biomedicine
Biochemistry & Molecular Biology
Gram-positive bacteria
protein structure
type IV pili
virulence factor
molecular motor
pilin
Streptococcus sanguinis
twitching motility
type IV filaments
II SECRETION SYSTEM
PSEUDOMONAS-AERUGINOSA
MINOR PILINS
STRUCTURE/FUNCTION ANALYSIS
CRYSTAL-STRUCTURE
ESCHERICHIA-COLI
LEADER PEPTIDE
REVEALS
PREPILIN
VISUALIZATION
Gram-positive bacteria
Streptococcus sanguinis
molecular motor
pilin
protein structure
twitching motility
type IV filaments
type IV pili
virulence factor
Biochemistry & Molecular Biology
06 Biological Sciences
11 Medical and Health Sciences
03 Chemical Sciences
Publication Status
Published
Date Publish Online
2019-03-05