Nuclear Magnetic Resonance and Conformational Energy Characterization of Repeat Peptides of Elastin: The Cyclohexadecapeptide, cyclo-(L-Val1-L-Pro2-Gly3-Gly4)4

Academic Article

Abstract

  • : The cyclohexadecapeptide cyclo-(L-Val1-L-Pro2-Gly3-Gly4)4 is synthesized and its conformational characteristics, in solution, are derived by employing 1H and 13C NMR methods. Selective decoupling and 13C {H} NOE are used to assign the 1H and 13C resonances in particular to delineate the two glycine residues in the molecule. Temperature and solvent dependence of peptide NH chemical shift are used to evaluate secondary structure. The dominant conformational feature of this molecule is shown to be a recurring type II β turn utilizing a hydrogen bond between the Gly4NH and Val1 C=O groups. T1values demonstrate increased flexibility of the chain segment, Gly4-Val1, which connects the β-turns. Comparable conformational features were also obtained by using in vacuo conformational energy calculations. The conformational properties of this cyclic molecule show a close relationship to its linear counterpart. The overall conformational behavior of the tetramer series is compared with the pentamer series, L-Val1L-Pro2-Gly3-L-Val4-Gly5, of elastin, particularly in terms of librations within the chain segments, Val4-Glys-Val1 and Gly4-Val1, connecting the β-turns. In analogy to the polypentapeptide study wherein a new mechanism of elasticity was developed, the present study represents a significant step in developing an understanding of the elasticity of the cross-linked polytetrapeptide of elastin. © 1985, American Chemical Society. All rights reserved.
  • Authors

    Digital Object Identifier (doi)

    Pubmed Id

  • 20645996
  • Author List

  • Urry DW; Prasad KU; Venkatachalam CM; Khaled MA
  • Start Page

  • 7139
  • End Page

  • 7145
  • Volume

  • 107
  • Issue

  • 24