Fig. 4

Characterisation of S. mansoni IR. a Sequence analysis of Schistosoma IR and in comparison with IR from other species. Top: The predicted protein domain organization of typical IR is shown in histogram. Below: Alignment of Schistosoma IR with IR proteins of representative selections from other species. Domains: TM, transmembrane domain; S, ligand-binding domain; P, pore. b Structure of S. mansoni IR as predicted by MDS model with space filling of predicted binding sites. Yellow shows the predicted ligand binding S1 region, green shows the predicted ligand binding S2 region, and blue demarcates the predicted TM regions. The protein domain structure of conventional IRs in cartoon form is shown below [40, 41]. c Schematic representation of all IRs shown in a, demonstrating conserved and invariable amino acids, as well as predicted S1 and S2 regions. d RT-PCR showing expression of IR in S. mansoni miracidia at 3 h and 6 h post-hatch (hph)