Cryo-EM structure of a conjugative type IV secretion system suggests a molecular switch regulating pilus biogenesis.
EMBO J
; 43(15): 3287-3306, 2024 Aug.
Article
de En
| MEDLINE
| ID: mdl-38886579
ABSTRACT
Conjugative type IV secretion systems (T4SS) mediate bacterial conjugation, a process that enables the unidirectional exchange of genetic materials between a donor and a recipient bacterial cell. Bacterial conjugation is the primary means by which antibiotic resistance genes spread among bacterial populations (Barlow 2009; Virolle et al, 2020). Conjugative T4SSs form pili long extracellular filaments that connect with recipient cells. Previously, we solved the cryo-electron microscopy (cryo-EM) structure of a conjugative T4SS. In this article, based on additional data, we present a more complete T4SS cryo-EM structure than that published earlier. Novel structural features include details of the mismatch symmetry within the OMCC, the presence of a fourth VirB8 subunit in the asymmetric unit of both the arches and the inner membrane complex (IMC), and a hydrophobic VirB5 tip in the distal end of the stalk. Additionally, we provide previously undescribed structural insights into the protein VirB10 and identify a novel regulation mechanism of T4SS-mediated pilus biogenesis by this protein, that we believe is a key checkpoint for this process.
Mots clés
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Fimbriae bactériens
/
Cryomicroscopie électronique
/
Systèmes de sécrétion de type IV
Langue:
En
Journal:
EMBO J
Année:
2024
Type de document:
Article
Pays de publication:
Royaume-Uni