THE SURFACE GLYCOCONJUGATES OF PARASITIC PROTOZOA - POTENTIAL TARGETSFOR NEW DRUGS

Protozoan parasites are the cause of many diseases in humans and their domestic livestock. Glycoconjugates (i.e. glycoproteins, glycolipids) on the cell surface of these extremely diverse and very primative euk aryotes play a crucial rot in determining the specificity of the host- parasite interaction and in protecting the parasites within their resp ective hosts. These molecules frequently share a common structural fea ture in that they are attached to the plasma membrane via a glycosylph osphatidylinositol (GPI) glycolipid. While GPI protein-membrane anchor s are ubiquitous among the eukaryotes, riley are used with exceptional ly high frequency in the protozoa. Some kinetopastid parasites also sy nthesise very high levels of GPI-related glycolipids that are not link ed to protein. Thus GPI-anchored molecules or free GPI glycolipids ten d to dominate the cell surface molecular architecture of these organis ms. The highly elevated levels and specialised nature of GPI metabolis m in rhp Kinetoplastid and other parasites suggests that the GPI biosy nthetic pathway might be a good target for the development of new chem otherapeutic agents. This article reviews the wide range of functions that GPI protein anchors and GPI-related glycolipids are thought to pe rform in these organisms and some aspects of their biosynthesis.