NMR and CD studies of triple‐helical peptides

Abstract

Triple-helix formation of the peptide (Pro-Hyp-Gly)10 was monitored by nmr and CD spectroscopy. The two-dimensional nmr spectra indicated that the Gly C alpha H and Pro C delta H proton resonances shift upfield in going from the nonhelical to helical form, while hydroxy-proline resonances are unchanged. The integrated areas of the helical and nonhelical resonances could be monitored in the one-dimensional nmr spectrum, and indicate that in the (Pro-Hyp-Gly)10 about 90% of the residues are in a defined triple-helical conformation. The introduction of a glycine to alanine substitution or the deletion of a single hydroxyproline residue in the stable triple-helical peptide (Pro-Hyp-Gly)10 still allows trimers to be formed, but the trimers show a substantial loss of triple helix and decreased thermal stability compared with (Pro-Hyp-Gly)10. Two computer models were generated for the Gly----Ala peptide, one with the Ala side chains packed inside the helix and the other with the region containing the alanines forming a beta-bend that loops out from the helix. The nmr data is more consistent with the latter model.

Thermal effects of added propanol on the helix–coil transition of (Pro-Pro-Gly)10 in D2O solution: An NMR study

“…1a. [Hereafter, Pro's at the X and Y positions are denoted as Pro(X) and Pro(Y), respectively, in the peptide sequence of (X-YGly) n .] This spectral feature was consistent with the characteristic set of interchain NOEs of triple helix [9,11,26,27]. Formation of the triple helix of PPG-10 in alcohol solutions was thus confirmed.…”

Perspectives on the synthesis and application of triple-helical, collagen-model peptides

“…The two-dimensional nmr techniques TOCSY (totally correlated spectroscopy) and NOESY (nuclear Overhauser enhancement spectroscopy) were used to assign Pro C,H proton and Gly C,H proton resonances in triple-helical and nontriple-helical (melted) (ProHyp-Gly)lo.35 One-dimensional 'H-nmr spectra showed a quantitative relationship between the Pro C,H and Gly C,H proton resonances and triple heli~ity.,'.~~ Specifically, the Pro C, H proton resonance at 3.2 ppm was present only in the triplehelical molecule, while the Gly C,H proton resonance at 4.2 ppm was present only in the nontriplehelical molecule, with the total area of these two peaks remaining constant during a triple-helical melt of ( Pro-Hyp-Gly),, .28, 35 The extent of triple and either ORD 18 …”

Multiple Binding Sites in Collagen Type I for the Integrins α1β1 and α2β1

“…The CD spectrum of the collagen triple helix shows a characteristic positive maximum ellipticity at 220 -225 nm (48). To examine the ability of each synthetic linear peptide to form a triple helix in solution, we monitored their CD spectra from 210 to 260 nm at various temperatures (4, 25, and 70°C) (Fig.…”