Figure 1. Tools for the isolation of TorAD complexes.

(A) A cartoon representing the structure of the torCAD operon located at 22.8 min on the E. coli chromosome. The names of the protein products of the genes are given above the arrows. (B) An overexpression vector based on pQE80 (Qiagen) encoding full-length TorA and TorD^His. The natural transcriptional and translational coupling between torA and torD is maintained. (C) An expression vector encoding TorA lacking its entire Tat signal peptide comprising Asn²–Ala³⁹ (TorA_Δsp, TorA Δ2–39) and TorD^His. (D) An expression vector encoding TorA lacking its entire C-terminal Domain IV comprising Ile⁶⁷⁶–Ser⁸⁴⁸ (TorA_ΔCT, TorA Δ676–848) and TorD^His.