On the molecular basis of the recognition of angiotensin II (AII). NMR structure of AII in solution compared with the X-ray structure of AII bound to the mAb Fab131.

Abstract

The high-resolution 3D structure of the octapeptide hormone angiotensin II (AII) in aqueous solution has been obtained by simulated annealing calculations, using high-resolution NMR-derived restraints. After final refinement in explicit water, a family of 13 structures was obtained with a backbone RMSD of 0.73 +/- 0.23 A. AII adopts a fairly compact folded structure, with its C-terminus and N-terminus approaching to within approximately 7.2 A of each other. The side chains of Arg2, Tyr4, Ile5 and His6 are oriented on one side of a plane defined by the peptide backbone, and the Val3 and Pro7 are pointing in opposite directions. The stabilization of the folded conformation can be explained by the stacking of the Val3 side chain with the Pro7 ring and by a hydrophobic cluster formed by the Tyr4, Ile5 and His6 side chains. Comparison between the NMR-derived structure of AII in aqueous solution and the refined crystal structure of the complex of AII with a high-affinity mAb (Fab131) [Garcia, K.C., Ronco, P.M., Verroust, P.J., Brunger, A.T., Amzel, L.M. (1992) Science257, 502-507] provides important quantitative information on two common structural features: (a) a U-shaped structure of the Tyr4-Ile5-His6-Pro7 sequence, which is the most immunogenic epitope of the peptide, with the Asp1 side chain oriented towards the interior of the turn approaching the C-terminus; (b) an Asx-turn-like motif with the side chain aspartate carboxyl group hydrogen-bonded to the main chain NH group of Arg2. It can be concluded that small rearrangements of the epitope 4-7 in the solution structure of AII are required by a mean value of 0.76 +/- 0.03 A for structure alignment and approximately 1.27 +/- 0.02 A for sequence alignment with the X-ray structure of AII bound to the mAb Fab131. These data are interpreted in terms of a biological "nucleus" conformation of the hormone in solution, which requires a limited number of structural rearrangements for receptor-antigen recognition and binding.

Statistics

0501002011201220132014201520162017
Citations per Year

fewer than 50 Citations

Semantic Scholar estimates that this publication has 50 citations based on the available data.

See our FAQ for additional information.

Cite this paper

@article{Tzakos2003OnTM, title={On the molecular basis of the recognition of angiotensin II (AII). NMR structure of AII in solution compared with the X-ray structure of AII bound to the mAb Fab131.}, author={Andreas G. Tzakos and Alexandre M. J. J. Bonvin and Anasstasios Troganis and Paul A. Cordopatis and Mario L Amzel and Ioannis P. Gerothanassis and Nico A. J. van Nuland}, journal={European journal of biochemistry}, year={2003}, volume={270 5}, pages={849-60} }