MOLECULAR AND BIOCHEMICAL-CHARACTERIZATION OF PHOSPHOGLUCOMUTASES FROM ENTAMOEBA-HISTOLYTICA AND ENTAMOEBA-DISPAR

Entamoeba histolytica and Entamoeba dispar have only recently been def ined as two separate species. E. histolytica, the pathogenic species, is the microorganism causing invasive intestinal amoebiasis and/or liv er abscess, while the morphologically similar E. dispar is nonpathogen ic and noninvasive. The gold standard for the distinction of the two s pecies has been the isoenzyme electrophoresis of phosphoglucomutases ( EC 5.4.2.2) and hexokinases (EC 2.7.1.1), but there had also been a co ntroversy about the possibility of a conversion of isoenzyme patterns. In this study, we cloned the phosphoglucomutase (PGM) cDNAs from the pathogenic and the nonpathogenic species. The deduced amino acid seque nces were only 2.4% different. The cDNAs were expressed in Escherichia coli under the control of a T7 RNA polymerase promoter. The recombina nt polypeptides displayed strong phosphoglucomutase activity, each of the recombinant enzymes comigrated with its natural counterpart from E . histolytica and E. dispar in the starch gel electrophoresis. Our res ults give a biochemical interpretation of the PGM isoenzyme pattern an d support the clear distinction between the two species. (C) 1997 Else vier Science B.V.