ApuA, a multifunctional alpha-glucan-degrading enzyme of Streptococcus suis, mediates adhesion to porcine epithelium and mucus.
We have identified apuA in Streptococcus suis, which encodes a bifunctional amylopullulanase with conserved alpha-amylase and pullulanase substrate-binding domains and catalytic motifs. ApuA exhibited properties typical of a Gram-positive surface protein, with a putative signal sequence and LPKTGE cell-wall-anchoring motif. A recombinant protein containing the predicted N-terminal alpha-amylase domain of ApuA was shown to have alpha-(1,4) glycosidic activity. Additionally, an apuA mutant of S. suis lacked the pullulanase alpha-(1,6) glycosidic activity detected in a cell-surface protein extract of wild-type S. suis. ApuA was required for normal growth in complex medium containing pullulan as the major carbon source, suggesting that this enzyme plays a role in nutrient acquisition in vivo via the degradation of glycogen and food-derived starch in the nasopharyngeal and oral cavities. ApuA was shown to promote adhesion to porcine epithelium and mucus in vitro, highlighting a link between carbohydrate utilization and the ability of S. suis to colonize and infect the host.
Ferrando
Maria Laura
ML
Host-Microbe Interactomics, Wageningen University and Research Centre, Marijkeweg 40, 6709 PG Wageningen, The Netherlands.
Fuentes
Susana
S
Host-Microbe Interactomics, Wageningen University and Research Centre, Marijkeweg 40, 6709 PG Wageningen, The Netherlands.
de Greeff
Astrid
A
Central Veterinary Institute of Wageningen UR, Edelhertweg 15, 8219 PH Lelystad, The Netherlands.
Smith
Hilde
H
Central Veterinary Institute of Wageningen UR, Edelhertweg 15, 8219 PH Lelystad, The Netherlands.
Wells
Jerry M
JM
Host-Microbe Interactomics, Wageningen University and Research Centre, Marijkeweg 40, 6709 PG Wageningen, The Netherlands.
D000818:Animals; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D005936:Glucans / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism / Q000382:microbiology*; D009093:Mucus / Q000378:metabolism / Q000382:microbiology*; D017434:Protein Structure, Tertiary; D013290:Streptococcal Infections / Q000378:metabolism / Q000382:microbiology / Q000662:veterinary*; D017011:Streptococcus suis / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D034421:Sus scrofa; D013552:Swine; D013553:Swine Diseases / Q000378:metabolism / Q000382:microbiology*
D001426:Bacterial Proteins; D005936:Glucans; C009109:pullulan; D006026:Glycoside Hydrolases; C082507:amylopullulanase