Cryo-EM reveals species-specific components within the Helicobacter pylori Cag type IV secretion system core complex.
Elife
; 92020 09 02.
Article
em En
| MEDLINE
| ID: mdl-32876048
ABSTRACT
The pathogenesis of Helicobacter pylori-associated gastric cancer is dependent on delivery of CagA into host cells through a type IV secretion system (T4SS). The H. pylori Cag T4SS includes a large membrane-spanning core complex containing five proteins, organized into an outer membrane cap (OMC), a periplasmic ring (PR) and a stalk. Here, we report cryo-EM reconstructions of a core complex lacking Cag3 and an improved map of the wild-type complex. We define the structures of two unique species-specific components (Cag3 and CagM) and show that Cag3 is structurally similar to CagT. Unexpectedly, components of the OMC are organized in a 11225 molar ratio (CagYCagXCagTCagMCag3). CagX and CagY are components of both the OMC and the PR and bridge the symmetry mismatch between these regions. These results reveal that assembly of the H. pylori T4SS core complex is dependent on incorporation of interwoven species-specific components.
Palavras-chave
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Helicobacter pylori
/
Sistemas de Secreção Tipo IV
Idioma:
En
Revista:
Elife
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Estados Unidos