Figure 5. Structure and backbone dynamics of the periplasmic domain of HasR.

(A) Overall structure of the HasR periplasmic domain. Top: cartoon diagram of the family of ten structures with lowest energy values (the flexible N- and C-termini are not presented). Bottom: (A) representative structure of the family (all residues are shown) with the linker containing the HasB/TonB box (magenta). The structure is rotated 180° around the Y axis. (B) Steady-state ¹⁵N-¹H NOE (C) relaxation rates R2 and (D) R1 were measured at 600 MHz at 20°C. (E) Structural comparison of the signaling domain of HasR with its two structural homologous. The loop 35–47 is surrounded.