ISSN:
0749-1581
Keywords:
1H NMR
;
13C NMR
;
nonapeptide collagen fragment
;
aluminium complex
;
cis, trans equilibrium
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
1H NMR studies at 250 MHz and 13C NMR studies at 62.8 MHz on the synthetic nonapeptide fragment of type III collagen, Gly-Lys-Hyp-Gly-Glu-Hyp-Gly-Pro-Lys (CP9), have been carried out in aqueous solution and DMSO-d6. The resonances are assigned with the help of 2D correlated spectroscopy, pH titrations by following the characteristic pK values exhibited by protons adjacent to ionization sites and one-dimensional (1D) spin decoupling techniques. Chemical shifts of the proline and hydroxylproline carbon atoms indicate that the trans configuration about the three X - Pro and X—Hyp peptide bonds is strongly favoured in all cases, although the minor cis resonances accounting for about 10% of the Pro and Hyp intensity can also be observed. In addition, there appears to be no significant pH sensitivity of the cis ⇌ trans equilibrium. Addition of aluminium causes changes in the spectra, indicating specific interactions with carboxylates of the glutamyl and lysyl residues, as well as a change for both hydroxylproline residues. These data are interpreted by the formation of a 1:2 stoichiometric complex (AlIII-CP9). the implication of these results with respect to the effect of aluminium in the tanning process is discussed.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260250709
Permalink
