Residues in a conserved α-helical segment are required for cleavage but not secretion of an Escherichia coli serine protease autotransporter passenger domain.
J Bacteriol
; 193(15): 3748-56, 2011 Aug.
Article
em En
| MEDLINE
| ID: mdl-21642456
ABSTRACT
Autotransporters are a superfamily of virulence factors produced by Gram-negative bacteria that are comprised of an N-terminal extracellular domain (passenger domain) and a C-terminal ß barrel domain (ß domain) that resides in the outer membrane (OM). The ß domain promotes the translocation of the passenger domain across the OM by an unknown mechanism. Available evidence indicates that an α-helical segment that spans the passenger domain-ß domain junction is embedded inside the ß domain at an early stage of assembly. Following its secretion, the passenger domain of the serine protease autotransporters of the Enterobacteriaceae (SPATEs) and the pertactin family of Bordetella pertussis autotransporters is released from the ß domain through an intrabarrel autoproteolytic cleavage of the α-helical segment. Although the mutation of conserved residues that surround the cleavage site has been reported to impair both the translocation and cleavage of the passenger domain of a SPATE called Tsh, we show here that the mutation of the same residues in another SPATE (EspP) affects only passenger domain cleavage. Our results strongly suggest that the conserved residues are required to position the α-helical segment for the cleavage reaction and are not required to promote passenger domain secretion.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Serina Endopeptidases
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Processamento de Proteína Pós-Traducional
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Proteínas de Escherichia coli
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Escherichia coli
Idioma:
En
Revista:
J Bacteriol
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Estados Unidos