Pore-forming peptides of Entamoeba dispar. Similarity and divergence to amoebapores in structure, expression and activity.
Amoebapore, a 77-residue peptide with pore-forming activity from the human pathogen Entamoeba histolytica, is implicated in the killing of phagocytosed bacteria and in the cytolytic reaction of the amoeba against host cells. Previously, we structurally and functionally characterized three amoebapore isoforms in E. histolytica but recognized only one homolog in the closely related but non-pathogenic species Entamoeba dispar. Here, we identified two novel amoebapore homologs from E. dispar by molecular cloning. Despite strong resemblance of the primary structures of the homologs, molecular modeling predicts a species-specific variance between the peptide structures. Parallel isolation from trophozoite extracts of the two species revealed a lower amount of pore-forming peptides in E. dispar and substantially higher activity of the major isoform from E. histolytica towards natural membranes than that from E. dispar. Differences in abundance and activity of the lytic polypeptides may have an impact on the pathogenicity of amoebae.
Nickel
R
R
Bernard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Ott
C
C
Dandekar
T
T
Leippe
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D004747:Entamoeba / Q000737:chemistry* / Q000235:genetics / Q000472:pathogenicity; D004748:Entamoeba histolytica / Q000737:chemistry / Q000235:genetics / Q000472:pathogenicity; D015870:Gene Expression; D006801:Humans; D007473:Ion Channels; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014774:Virulence
D017931:DNA Primers; D007473:Ion Channels; D008565:Membrane Proteins; D020033:Protein Isoforms; D015800:Protozoan Proteins; C041670:amoebapore proteins, protozoan