Entamoeba histolytica: molecular characterization of an aldose 1-epimerase (mutarotase).
In cells, the alpha-anomers of aldoses are the preferred metabolizable substrates, while beta-anomers of aldoses play their role in glycan structure. In the cytoplasm, alpha- and beta-anomers of aldoses interconvert through the enzyme termed aldose 1-epimerase or mutarotase (EC 5.1.3.3). We have identified a mutarotase gene in Entamoeba histolytica, the causative agent of non-bacterial dysentery in humans. Cloning and characterization of this gene in two strains of the parasite (HM-1:IMSS and Rahman) that differ in their pathogenicity, revealed that the sequence is identical in both strains. A recombinant E. histolytica mutarotase was produced as well as specific antibodies that recognized a 38 kDa protein in trophozoite lysates of both strains. Mutarotase activity was observed with the recombinant protein as well as in lysates of both HM-1:IMSS and Rahman, the former exhibiting a slightly higher mutarotase activity. Finally, we have shown by complementation that overexpression of the E. histolytica mutarotase in a mutarotase defective Escherichia coli strain restores the ability of these bacteria to grow in minimal medium with phenyl-beta-galactopyranoside as the sole carbon source.
Villalobo
Eduardo
E
Department of Biological Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel. evpolo@us.es
Wender
Nomy
N
Mirelman
David
D
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002238:Carbohydrate Epimerases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry; D016054:DNA, Protozoan / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D004748:Entamoeba histolytica / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment
D018076:DNA, Complementary; D016054:DNA, Protozoan; D002238:Carbohydrate Epimerases; C019646:aldose 1-epimerase