Skip to main content
. 2021 Feb 8;10:e64302. doi: 10.7554/eLife.64302

Figure 2. EmrE(Cout).

(a) Construct design. EmrE(Cout) is shortened from the C-terminal end of the LepB-derived linker (dotted), as indicated by the arrow. Cytoplasmic (red) and periplasmic (blue) loops, and lengths of full-length EmrE(Cout), LepB-derived linker, HA tag + arrest peptide (AP), and C-terminal tail, are indicated. Since the 30-residue HA + AP segment is constant in all constructs, the force profile (FP) reflects nascent chain interactions occurring mainly outside the ribosome exit tunnel. (b) FPs for EmrE(Cout) (orange), EmrE(Cout,E14L) (green), EmrE(Cout) with SecM(Ec-sup1) AP (blue), EmrE(Cout, I37I38→NN) (magenta triangles), and coarse-grained molecular dynamics (CGMD-FP) calculated with a −100 mV membrane potential (gray). (c) Effects of mutations in E14 on fFL values for the N values are indicated by arrows in (b). p-values (two-sided t-test): *p < 0.05; **p < 0.01; ***p < 0.001. (d, e) Sequences corresponding to peaks I–IV aligned from their Nstart (d) and Nend (e) values. The + sign indicates 45 residues from the polypeptide transferase center (PTC). Hydrophobic transmembrane helix (TMH) segments are shown in orange and transmembrane α-helices underlined (PDB: 3B5D). Error bars in b and c indicate SEM values.

Figure 2.

Figure 2—figure supplement 1. EmrE(Cout).

Figure 2—figure supplement 1.

As in Figure 2b, but with a hydrophobicity plot (HP) (ΔG) calculated by TOPCONS (3, 50) (gray). Since the HP represents the membrane integration energy, and the force profile (FP) the force generated during integration, the two profiles have been aligned such that peaks in the FP approximately align with maxima in the derivative of the HP.