Sotlillm clodtq~l sul~~t~e/polyacrylarnide gel :tnwlysis ot’ protrins t~codcd by ii sc>rics ot’ to?/ R + plasmids in minicells has icknt~ified the torLB gene product ws a prokin wit)h km apparent, molecular weight of’ 36,000. A parallel analysis of s(‘vcn tort N mnt,ations which have been genetically crosst~i onto a tonB+ plasmid support,s this itkntification; t)he 36,000 M, protein is tlbsent ...