| Abstract
| - Angiotensin II (Ang II) is an octapeptidic hormone, which plays an important role in the mechanisms ofblood pressure control. In this work, extensive molecular dynamics (MD) simulations have been carried outon this peptide, both in aqueous and in dimethyl sulfoxide (DMSO) environments. Experimentally proposedmodels for the structure of angiotensin II in both environments are not consensual and the results obtainedhave provided some further insight about the structural properties of this hormone. In these simulations, theN-terminus of Ang II in the aqueous environment has been associated with a considerable larger flexibilitythan the correspondent C-terminus, but this was not found in the case of the DMSO environment. This isconsistent with the assumption that the biological activity of Ang II is associated with its C-terminal residuesembedded in a hydrophobic environment of its AT1 receptor. Other features detected in DMSO environmentwere an H(His6 imidazole)−O(Phe8 carboxylate) hydrogen bond and a salt-bridge structure involving theAsp1 and Arg2 side chains. An additional important conformational feature is the spatial proximity betweenTyr4 and His6 in both water and DMSO environments. This molecular feature may trigger the interest forthe synthetic chemists to apply rational design for the synthesis of novel AT1 antagonists.
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