RT Journal Article SR Electronic T1 Engineering Photorhabdus luminescens toxin complex (PTC) into a recombinant injection nanomachine JF Life Science Alliance JO Life Sci. Alliance FD Life Science Alliance LLC SP e201900485 DO 10.26508/lsa.201900485 VO 2 IS 5 A1 Peter Njenga Ng´ang´a A1 Julia K Ebner A1 Matthias Plessner A1 Klaus Aktories A1 Gudula Schmidt YR 2019 UL https://www.life-science-alliance.org/content/2/5/e201900485.abstract AB Engineering delivery systems for proteins and peptides into mammalian cells is an ongoing challenge for cell biological studies as well as for therapeutic approaches. Photorhabdus luminescens toxin complex (PTC) is a heterotrimeric protein complex able to deliver diverse protein toxins into mammalian cells. We engineered the syringe-like nanomachine for delivery of protein toxins from different species. In addition, we loaded the highly active copepod luciferase Metridia longa M-Luc7 for accurate quantification of injected molecules. We suggest that besides the probable size limitation, the charge of the cargo also influences the efficiency of packing and transport into mammalian cells. Our data show that the PTC constitutes a powerful system to inject recombinant proteins, peptides, and potentially, other molecules into mammalian cells. In addition, in contrast to other protein transporters based on pore formation, the closed, compact structure of the PTC may protect cargo from degradation.