Discussion

Leishmania tarentolae is a save (biosafety group S1), robust and easy-to-culture protozoan organism with the full capacity for eukaryotic protein folding and modification including mammalian-type post-translational glycosylation. We have developed this organism into the flexible and efficient protein expression platform called LEXSY. Recombinant proteins can be expressed intracellularly or be secreted into the culturing medium. Both, constitutive and inducible expression architectures are available. Up to 6 polypeptides can be co-expressed per clone, enabling assembly of hetero-oligomeric complexes. Numerous proteins, including enzymes, surface antigens, toxins, antibodies and membrane proteins have been functionally expressed with LEXSY. Yields of up to several hundred mg per litre of culture were obtained, and the purified proteins were successfully employed for diagnostics and R&D including structure determination by NMR and X-ray crystallography. LEXSY was successfully applied for expression of Leishmania and Trypanosoma proteins. It is also available as in vitro version for cell-free expression of recombinant proteins.