|Beschreibung:||The caenopore-5 protein encoded by the spp-5 gene is one out of 23 caenopores identified in C.elegans. It belongs to the SAPLIP family whose members perform a variety of functions based on their ability to interact with lipids. It has been shown that caenopore-5 is responsible for the survival and growth of C.elegans on E.coli lawns. The main aim of this project was the determination of the three-dimensional structure of caenopore-5 by means of NMR spectroscopy. The sequential assignment revealed two conformers of caenopore-5. Separate structure calculations for the two sets of distance constraints, which correspond to the two different conformers of caenopore-5 revealed that they only differ in the isomerisation of Pro 99.The structure of caenopore-5 displays the saposin-like fold characteristic of the SAPLIP family. It consists of five amphiphatic alpha helices connected by short loops or a kink. They are all arranged in the tertiary structure which resembles a folded leaf stabilised by three disulphide bridges made of six conserved cysteines. Interestingly, the comparison of the caenopore-5 structure with structures of other members of the SAPLIP family revealed that two non-antimicrobial peptides saposin A and C are the most similar. Furthermore, caenopore-5 shows a remarkable preference for the interaction with negatively charged phosphatidylglycerol liposomes, which served as a model for bacterial membranes. This interaction induced a conformational change in caenopore-5. The knowledge of the tertiary structure now provides the basis for further studies of the Caenopore-5 function.