Figure 4.

LptC-LptA_m interaction by NMR spectroscopy. (a) [¹H, ¹⁵N]-correlation spectrum of [²H, ¹⁵N]-labeled LptA_m in absence (green) and presence (red) of 1.2 molar equivalent of [¹H, ¹⁴N]-LptC. (b) [¹H, ¹³C]-correlation spectrum of LptC specifically ¹³C labeled and protonated on A^βI^δ1L^δ1V^γ1 methyl groups in absence (black) and presence (red) of 1.2 equivalent [¹H, ¹²C]-LptA_m. (c) and (d) Chemical shift perturbation induced upon complex formation on LptA_m and LptC proteins, respectively. Two regions of LptA_m and LptC are perturbed upon complex formation (light red boxes), the N-terminus and C-terminus of the proteins, respectively. These regions are represented in red on the ribbon structures of (e) LptA_m (residues 29–159) and (f) LptC (residues 56–185). The right panels in (e) and (f) show LtpA_m and LptC in the same orientation as in the left panel with a blue-to-red gradient from N- to C-termini of the proteins.