GamA is a eukaryotic-like glucoamylase responsible for glycogen- and starch-degrading activity of Legionella pneumophila.
Legionella pneumophila (Lp) is the causative agent of Legionnaires' disease, an atypical pneumonia. Lp is found in freshwater habitats and replicates within different protozoa (amoebae). It is known that Lp uses amino acids as primary energy and carbon sources for replication. However, very recently it was reported that Lp is able to metabolize also carbohydrates (glucose). Here, we present for the first time experimental evidence that the lpp0489 [gamA] gene encodes a eukaryotic-like glucoamylase (GamA) responsible for the glycogen- and starch-degrading activities of Lp. Although not essential for intra- and extracellular growth, we showed that GamA is expressed and active during intracellular replication in Acanthamoeba castellanii, suggesting that Lp is degrading glycogen during intracellular replication. Altogether, these findings indicate that Lp is indeed able to degrade exogenous polysaccharides and to utilize carbohydrates (glucose).
Robert Koch-Institut, Research Group P26, Nosocomial Infections of the Elderly, Nordufer 20, 13353 Berlin, Germany.
Vroni
V
Herrmann
Anja
A
Eidner
Kerstin
K
Rydzewski
Inga
I
Blädel
Matthieu
M
Jules
Carmen
C
Buchrieser
Wolfgang
W
Eisenreich
Klaus
K
Heuner
D048248:Acanthamoeba castellanii / Q000382:microbiology; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D005087:Glucan 1,4-alpha-Glucosidase / Q000235:genetics* / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism*; D016952:Legionella pneumophila / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D013213:Starch / Q000378:metabolism*
D013213:Starch; D006003:Glycogen; D005087:Glucan 1,4-alpha-Glucosidase