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Characterization of SfPgdA, a Shigella flexneri peptidoglycan deacetylase required for bacterial persistence within polymorphonuclear neutrophils.
Kaoukab-Raji, Abdelmoughit; Biskri, Latéfa; Bernardini, Maria-Lina; Allaoui, Abdelmounaaïm.
Afiliación
  • Kaoukab-Raji A; Laboratoire de Bactériologie Moléculaire, Faculté de Médecine, Université Libre de Bruxelles, Route de Lennik 808, 1070 Bruxelles, Belgium.
Microbes Infect ; 14(7-8): 619-27, 2012 Jul.
Article en En | MEDLINE | ID: mdl-22307019
Peptidoglycan deacetylases protect the Gram-positive bacteria cell wall from host lysozymes by deacetylating peptidoglycan. Sequence analysis of the genome of Shigella flexneri predicts a putative polysaccharide deacetylase encoded by the plasmidic gene orf185, renamed here SfpgdA. We demonstrated a peptidoglycan deacetylase (PGD) activity with the purified SfPgdA in vitro. To investigate the role SfPgdA in virulence, we constructed a SfpgdA mutant and studied its phenotype in vitro. The mutant showed an increased sensitivity to lysozyme compared to the parental strain. Moreover, the mutant was rapidly killed by polymorphonuclear neutrophils (PMNs). Specific substitution of histidines residues 120 and 125, located within the PGD catalytic domain, by phenylalanine abolished SfPgdA function. SfPgdA expression is controlled by PhoP. Mutation of phoP increases sensitivity to lysozyme compared to the SfpgdA mutant. Here, we confirmed that SfPgdA expression is enhanced under low magnesium concentration and not produced by the phoP mutant. Ectopic expression of SfPgdA in the phoP mutant restored lysozyme resistance and parental bacterial persistence within PMNs. Together our results indicate that PG deacetylation mechanism likely contributes to Shigella persistence by subverting detection by the host immune system.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Acetilesterasa / Shigella flexneri / Disentería Bacilar / Amidohidrolasas / Neutrófilos Límite: Child, preschool / Humans / Infant Idioma: En Revista: Microbes Infect Asunto de la revista: ALERGIA E IMUNOLOGIA / MICROBIOLOGIA Año: 2012 Tipo del documento: Article País de afiliación: Bélgica Pais de publicación: Francia

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Acetilesterasa / Shigella flexneri / Disentería Bacilar / Amidohidrolasas / Neutrófilos Límite: Child, preschool / Humans / Infant Idioma: En Revista: Microbes Infect Asunto de la revista: ALERGIA E IMUNOLOGIA / MICROBIOLOGIA Año: 2012 Tipo del documento: Article País de afiliación: Bélgica Pais de publicación: Francia