Differential requirements for processing and transport of short-chain versus long-chain O-acylcarnitines in Pseudomonas aeruginosa.
Microbiology (Reading)
; 164(4): 635-645, 2018 04.
Article
em En
| MEDLINE
| ID: mdl-29517479
ABSTRACT
The opportunistic pathogen Pseudomonas aeruginosa can metabolize carnitine and O-acylcarnitines, which are abundant in host muscle and other tissues. Acylcarnitines are metabolized to carnitine and a fatty acid. The liberated carnitine and its catabolic product, glycine betaine, can be used as osmoprotectants, to induce the secreted phospholipase C PlcH, and as sole carbon, nitrogen and energy sources. P. aeruginosa is incapable of de novo synthesis of carnitine and acylcarnitines, therefore they must be imported from an exogenous source. In this study, we present the first characterization of bacterial acylcarnitine transport. Short-chain acylcarnitines are imported by the ABC transporter CaiX-CbcWV. Medium- and long-chain acylcarnitines (MCACs and LCACs) are hydrolysed extracytoplasmically and the free carnitine is transported primarily through CaiX-CbcWV. These findings suggest that the periplasmic protein CaiX has a binding pocket that permits short acyl chains on its carnitine ligand and that there are one or more secreted hydrolases that cleave MCACs and LCACs. To identify the secreted hydrolase(s), we used a saturating genetic screen and transcriptomics followed by phenotypic analyses, but neither led to identification of a contributing hydrolase, supporting but not conclusively demonstrating redundancy for this activity.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pseudomonas aeruginosa
/
Carnitina
/
Proteínas de Transporte
/
Transportadores de Cassetes de Ligação de ATP
/
Hidrolases
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Microbiology (Reading)
Assunto da revista:
MICROBIOLOGIA
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Estados Unidos