IcmQ in the Type 4b secretion system contains an NAD+ binding domain.
Structure
; 21(8): 1361-73, 2013 Aug 06.
Article
en En
| MEDLINE
| ID: mdl-23850453
A Type 4b secretion system (T4bSS) is required for Legionella growth in alveolar macrophages. IcmQ associates with IcmR, binds to membranes, and has a critical role in the T4bSS. We have now solved a crystal structure of IcmR-IcmQ to further our understanding of this complex. This structure revealed an amphipathic four-helix bundle, formed by IcmR and the N-terminal domain of IcmQ, which is linked to a novel C-terminal domain of IcmQ (Qc) by a linker helix. The Qc domain has structural homology with ADP ribosyltransferase domains in certain bacterial toxins and binds NAD(+) with a dissociation constant in the physiological range. Structural homology and molecular dynamics were used to identify an extended NAD(+) binding site on Qc, and the resulting model was tested by mutagenesis and binding assays. Based on the data, we suggest that IcmR-IcmQ binds to membranes, where it may interact with, or perhaps modify, a protein in the T4bSS when NAD(+) is bound.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas Bacterianas
/
Legionella pneumophila
/
NAD
Idioma:
En
Revista:
Structure
Asunto de la revista:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
/
BIOTECNOLOGIA
Año:
2013
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos