MOLECULAR CHARACTERIZATION OF AN EXCEPTIONALLY ACIDIC LYSOZYME-LIKE PROTEIN FROM THE PROTOZOAN ENTAMOEBA-HISTOLYTICA

The protozoan parasite Entamoeba histolytica contains a second antibac terial protein with lysozyme-like properties. The newly recognized bac teriolytic protein was purified from extracts of amoebic trophozoites to allow amino-terminal sequencing. Subsequent molecular cloning revea led that it is an isoform of the amoeba lysozyme described previously but also demonstrated a substantial sequence divergence of the two for ms. As lysozymes typically are basic proteins, the novel amoebic prote in differs markedly in having a pI of 4.5. There is no significant sim ilarity of both amoeba lysozymes with any bacteriolytic protein of oth er organisms reported so far; however, striking sequence identity is f ound with predicted gene products of unknown function derived from the bacteria-feeding nematode Caenorhabditis elegans. (C) 1998 Federation of European Biochemical Societies.