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Contribution of AmyA, an extracellular alpha-glucan degrading enzyme, to group A streptococcal host-pathogen interaction.

ABSTRACT: alpha-Glucans such as starch and glycogen are abundant in the human oropharynx, the main site of group A Streptococcus (GAS) infection. However, the role in pathogenesis of GAS extracellular alpha-glucan binding and degrading enzymes is unknown. The serotype M1 GAS genome encodes two extracellular proteins putatively involved in alpha-glucan binding and degradation; pulA encodes a cell wall anchored pullulanase and amyA encodes a freely secreted putative cyclomaltodextrin alpha-glucanotransferase. Genetic inactivation of amyA, but not pulA, abolished GAS alpha-glucan degradation. The DeltaamyA strain had a slower rate of translocation across human pharyngeal epithelial cells. Consistent with this finding, the DeltaamyA strain was less virulent following mouse mucosal challenge. Recombinant AmyA degraded alpha-glucans into beta-cyclomaltodextrins that reduced pharyngeal cell transepithelial resistance, providing a physiologic explanation for the observed transepithelial migration phenotype. Higher amyA transcript levels were present in serotype M1 GAS strains causing invasive infection compared with strains causing pharyngitis. GAS proliferation in a defined alpha-glucan-containing medium was dependent on the presence of human salivary alpha-amylase. These data delineate the molecular mechanisms by which alpha-glucan degradation contributes to GAS host-pathogen interaction, including how GAS uses human salivary alpha-amylase for its own metabolic benefit.

SUBMITTER: Shelburne Iii SA

PROVIDER: S-EPMC4557622 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature

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Contribution of AmyA, an extracellular alpha-glucan degrading enzyme, to group A streptococcal host-pathogen interaction.

Shelburne Iii Samuel A SA Keith David B DB Davenport Michael T MT Beres Stephen B SB Carroll Ronan K RK Musser James M JM

Molecular microbiology 20090903 1

alpha-Glucans such as starch and glycogen are abundant in the human oropharynx, the main site of group A Streptococcus (GAS) infection. However, the role in pathogenesis of GAS extracellular alpha-glucan binding and degrading enzymes is unknown. The serotype M1 GAS genome encodes two extracellular proteins putatively involved in alpha-glucan binding and degradation; pulA encodes a cell wall anchored pullulanase and amyA encodes a freely secreted putative cyclomaltodextrin alpha-glucanotransferas ...[more]

PMID: 19735442

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Dataset Information

Contribution of AmyA, an extracellular alpha-glucan degrading enzyme, to group A streptococcal host-pathogen interaction.

Publications

Contribution of AmyA, an extracellular alpha-glucan degrading enzyme, to group A streptococcal host-pathogen interaction.

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