Detailed proton magnetic resonance data, obtained in chloroform-dimethyl sulfoxide solutions, are reported and utilized to derive a static approximation to the conformation of the repeat hexapeptide of tropoelastin, HCO-L-Ala1-L-Pro2-Gly3-L-Val4-Gly5-L-Val6-OMe. The experimental information includes data and analyses of all of the αCH-NH and the valyl αCH-βCH coupling constants allowing estimates of five ø and two×torsion angles, of temperature dependence of peptide NH chemical shift providing information on secondary structure, of nuclear Overhauser enhancement data allowing estimates of two Ψtorsion angles. The secondary structure and torsion angle data are self-consistent giving rise to a satisfactory static model. Conformational energy calculations in vacuo are also reported for the hexapeptide which describe two conformational states one of which compares favorably with the experimentally derived conformation. Adding to the static model a Val6,i-l residue preceding the hexapeptide and fixing the ø and Ψ angles of both Val6 residues at the theoretically derived values allows formation of a 23-atom hydrogen-bonded ring which had previously been deduced in solution for the polyhexapeptide. © 1978, American Chemical Society. All rights reserved.