We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Contribution of AmyA, an extracellular α-glucan degrading enzyme, to group A streptococcal host–pathogen interaction.
- Authors
Shelburne III, Samuel A.; Keith, David B.; Davenport, Michael T.; Beres, Stephen B.; Carroll, Ronan K.; Musser, James M.
- Abstract
α-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 α-glucan binding and degrading enzymes is unknown. The serotype M1 GAS genome encodes two extracellular proteins putatively involved in α-glucan binding and degradation; pulA encodes a cell wall anchored pullulanase and amyA encodes a freely secreted putative cyclomaltodextrin α-glucanotransferase. Genetic inactivation of amyA, but not pulA, abolished GAS α-glucan degradation. The Δ amyA strain had a slower rate of translocation across human pharyngeal epithelial cells. Consistent with this finding, the Δ amyA strain was less virulent following mouse mucosal challenge. Recombinant AmyA degraded α-glucans into β-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 α-glucan-containing medium was dependent on the presence of human salivary α-amylase. These data delineate the molecular mechanisms by which α-glucan degradation contributes to GAS host–pathogen interaction, including how GAS uses human salivary α-amylase for its own metabolic benefit.
- Subjects
GLUCANS; STARCH; GLYCOGEN; STREPTOCOCCUS; PATHOGENIC microorganisms; ENZYMES; GENOMES
- Publication
Molecular Microbiology, 2009, Vol 74, Issue 1, p159
- ISSN
0950-382X
- Publication type
Article
- DOI
10.1111/j.1365-2958.2009.06858.x