Processing by inverted plasma membrane vesicles of in vitro synthesized major lipoprotein from Escherichia coli

Synthesis, lipid modification and proteolytic processing of the major lipoprotein from Escherichia coli is shown to occur in a homologous in vitro transcription-translation system containing inverted plasma membrane vesicles. The primary translation product (cross-reacting with anti-lipoprotein antiserum) is a precursor which is converted into a lower molecular mass species of the size of mature lipoprotein by the addition of inverted membrane vesicles from E. coli. Conversion is prevented by globomycin, a specific inhibitor of the unique lipoprotein-signal peptidase II, which is active only on lipid-containing precursors. The inverted plasma membrane vesicles used here must therefore contain active lipid-modifying enzymes and signal peptidase II.