Figure 5.

Conformational changes of angiotensinogen upon renin interaction. Side views of AGT alone (A) and from the complex with renin (B) illustrate the substantial movement of the N terminus of AGT into the renin active cleft. The scissile bond (shown as spheres) moves 18.6 Å during the complex formation. The color coding and abbreviations are the same as in Fig. 1. C, superposed structures of native AGT and AGT from the complex with renin show significant structural rearrangement of helices H, A, I, and J (hH, hA, hI, and hJ) of AGT upon renin binding. Native AGT is shown as gray with a cyan helix H, and AGT in the complex is color-coded as AGT in Fig. 1. Helix H is completely unwound with the C^α atom of Asn³³¹ (shown as a cyan stick in native AGT and red stick in AGT complexed with renin) shifting more than 6 Å to interact with Tyr⁶⁰ of renin. Helix A is extended by two turns with the side chain of Trp⁹² (shown as a magenta stick in native AGT and a marine stick in AGT complexed with renin) at the tip of helix A being flipped out. D, superposed structures of native (gray) and spent AGT (same color coding as AGT in Fig. 1) show that spent AGT largely resembles native AGT, but with differences in helix H and the CD-loop (blue in spent AGT). Helix H of spent AGT is completely disordered.