ectodomain of Trypanosoma, including T. brucei Procyclic-Specific Surface Antigen-2 (TbPSSA-2), T. congolense Insect Stage Antigen (TcISA), and similar proteins
This family includes the ectodomains of Trypanosoma brucei Procyclic-Specific Surface Antigen-2 (TbPSSA-2) and homolog T. congolense Insect Stage Antigen (TcISA). Trypanosomal parasites transmit disease through the arthropod vector Glossina spp (the tsetse fly). Studies have shown that TbPSSA-2 plays an important role in parasite survival in the tsetse; TbPSSA-2 knock-out reduced the efficiency of trypanosome migration from the tsetse midgut to the salivary glands. The TbPSSA-2 and TcISA ectodomains adopt a novel architecture, having two lobes connected by a loop, exhibiting conformational flexibility. The inter-lobe hinge region displaying rotational flexibility suggests a potential mechanism for coordinating a binding partner.