Figure 5.
Influence of DCCD on the premature cleavage of a Tat-signal peptide in the absence of TatB. Autoradiographies are shown. TorA–mCherry was synthesized and radioactively labeled in vitro. a, samples were treated with DMSO, CCCP, or DCCD as indicated, before adding vesicles (INV) containing either TatABC or only TatA and TatC. Upon addition of TatABC vesicles, the precursor of TorA–mCherry (p) is processed to the mature form (m). Transport into INV is indicated by proteinase K (PK) resistance. The PK-resistant precursor is of slightly reduced size because of the removal a few N-terminal amino acids by PK. When TatAC vesicles were used, digestion of precursor (p) and mature forms (m) by PK indicates a lack of transport due to the missing TatB. The translocation-independent processing of the precursor to the mature form was quantified from three independent experiments. b, samples were treated as in a before adding vesicles containing only TatA and the TatCE170A variant.