Conformational analysis and stability of collagen peptides by CD and by1H- and13C-NMR spectroscopies

Consonni, Roberto; Zetta, Lucia; Longhi, Renato; Toma, Lucio; Zanaboni, Giuseppe; Tenni, Ruggero

doi:10.1002/(sici)1097-0282(200001)53:1<99::aid-bip9>3.0.co;2-d

Cited by 15 publications

(6 citation statements)

References 51 publications

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“…In agreement with this, earlier results we obtained on CNBr peptides from collagens I and II have shown that: (a) a high percentage of single‐stranded monomeric peptides is able to form trimeric species, after long standing at low temperature [15,16]; (b) repeated denaturation of the trimeric species of peptide α1(I) CB2 was fully reversible at acidic pH after long standing at 4–5°C, as seen by nuclear magnetic resonance (NMR) spectroscopy; furthermore, the melting transition curves determined at the level of peptide bonds by CD measurements and for an amino acid side chain by NMR were superimposable [17]; (c) by using trypsin at neutral pH, the trimeric species of CNBr peptides have a half‐life of 1.5–4 days at 4°C and a few hours at 20°C [15].…”

Section: Discussionsupporting

confidence: 83%

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Molecular stability of chemically modified collagen triple helices

Giudici¹,

Viola²,

Tira³

et al. 2003

FEBS Letters

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Ionic residues in£uence the stability of collagen triple helices and play a relevant role in the spontaneous aggregation of ¢brillar collagens. Collagen types I and II and some of their CNBr peptides were chemically modi¢ed in mild conditions with two di¡erent protocols. Primary amino groups of Lys and Hyl were N-methylated by formaldehyde in reducing conditions or N-acetylated by sulfosuccinimidyl acetate. The positive charge of amino groups at physiological pH was maintained after the former modi¢cation, whereas it was lost after the latter. These chemical derivatizations did not signi¢cantly alter the stability of the triple helical conformation of peptide trimeric species. Also the enthalpic change on denaturation was largely unaffected by derivatizations. This implies that no signi¢cant variation of weak bonds, either in number or overall strength, and of entropy occur on modi¢cation. These properties can probably be explained by the fact that chemically modi¢ed groups maintain the ability to form hydrogen bonds. ß

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Section: Discussionsupporting

confidence: 83%

“…Acid‐soluble type I collagen from bovine skin and its CNBr peptides were prepared and characterized, as described in [15–18]. Pepsinized type II collagen was purified from bovine nasal septum, essentially as described in [19].…”

Section: Methodsmentioning

confidence: 99%

Molecular stability of chemically modified collagen triple helices

Giudici¹,

Viola²,

Tira³

et al. 2003

FEBS Letters

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“…A very important parameter related to the peak intensities is the absolute value of the ratio of the dichroic intensity of the positive peak to the negative peak (R pn ), which can be considered as an index for triple helicity (39,40). During thermal denaturation the positive peak near 220-225 nm disappears and the intensity of the negative peak is decreased (36,39,41).…”

Section: CDmentioning

confidence: 99%

Electrostatic Interactions Modulate the Conformation of Collagen I

Freudenberg

Behrens²,

Welzel

et al. 2007

Biophysical Journal

104

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The pH- and electrolyte-dependent charging of collagen I fibrils was analyzed by streaming potential/streaming current experiments using the Microslit Electrokinetic Setup. Differential scanning calorimetry and circular dichroism spectroscopy were applied in similar electrolyte solutions to characterize the influence of electrostatic interactions on the conformational stability of the protein. The acid base behavior of collagen I was found to be strongly influenced by the ionic strength in KCl as well as in CaCl(2) solutions. An increase of the ionic strength with KCl from 10(-4) M to 10(-2) M shifts the isoelectric point (IEP) of the protein from pH 7.5 to 5.3. However, a similar increase of the ionic strength in CaCl(2) solutions shifts the IEP from 7.5 to above pH 9. Enhanced thermal stability with increasing ionic strength was observed by differential scanning calorimetry in both electrolyte systems. In line with this, circular dichroism spectroscopy results show an increase of the helicity with increasing ionic strength. Better screening of charged residues and the formation of salt bridges are assumed to cause the stabilization of collagen I with increasing ionic strength in both electrolyte systems. Preferential adsorption of hydroxide ions onto intrinsically uncharged sites in KCl solutions and calcium binding to negatively charged carboxylic acid moieties in CaCl(2) solutions are concluded to shift the IEP and influence the conformational stability of the protein.

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“…33,34 Recent studies compared a synthetic peptide of the same sequence with that obtained following CNBr cleavage and purification and found similar properties, but a slightly higher stability. 35 Synthetic peptides have been designed with specific regions of collagen sequences involved in binding, recognition, and cleavage sites. These peptides typically contain Gly-Pro-Hyp or Gly-Pro-Pro repeating sequences at one or both ends of the real collagen sequences.…”

Section: Peptides Including Collagen Sequencesmentioning

confidence: 99%