Thermal stability of collagen fibers in ethylene glycol.


Abstract

The mechanism that renders collagen molecules more stable when precipitated as fibers than the same molecules in solution is controversial. According to the polymer-melting mechanism the presence of a solvent depresses the melting point of the polymer due to a thermodynamic mechanism resembling the depression of the freezing point of a solvent due to the presence of a solute. On the other hand, according to the polymer-in-a-box mechanism, the change in configurational entropy of the collagen molecule on denaturation is reduced by its confinement by surrounding molecules in the fiber. Both mechanisms predict an approximately linear increase in the reciprocal of the denaturation temperature with the volume fraction (epsilon) of solvent, but the polymer-melting mechanism predicts that the slope is inversely proportional to the molecular mass of the solvent (M), whereas the polymer-in-a-box mechanism predicts a slope that is independent of M. Differential scanning calorimetry was used to measure the denaturation temperature of collagen in different concentrations of ethylene glycol (M = 62) and the slope found to be (7.29 +/- 0.37) x 10(-4) K(-1), compared with (7.31 +/- 0.42) x 10(-4) K(-1) for water (M = 18). This behavior was consistent with the polymer-in-a-box mechanism but conflicts with the polymer-melting mechanism. Calorimetry showed that the enthalpy of denaturation of collagen fibers in ethylene glycol was high, varied only slowly within the glycol volume fraction range 0.2 to 1, and fell rapidly at low epsilon. That this was caused by the disruption of a network of hydrogen-bonded glycol molecules surrounding the collagen is the most likely explanation. Study holds ProTherm entries: 10517, 10518 Extra Details: dH=5.41 (kJ/mol residue), dCp=0.15 (J/g/K). Solvent is 0.5 M acetic acid in water. Scanning rate = 0.25 K/min. polymer-melting mechanism; thermodynamic mechanism;,surrounding molecules; hydrogen-bonded network

Submission Details

ID: 7aVvS2sL3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:40 p.m.

Version: 1

Publication Details
Miles CA;Burjanadze TV,Biophys. J. (2001) Thermal stability of collagen fibers in ethylene glycol. PMID:11222308
Additional Information

Number of data points 2
Proteins Type 1 Collagen ; Collagen alpha-1(I) chain
Unique complexes 1
Assays/Quantities/Protocols Experimental Assay: Tm
Libraries Mutations for sequence A: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:EFDAKGGGPGPMGLMGPRGPPGASGAPGPQGFQGPPGEPGEPGQTGPAGARGPPGPPGKAGEDGHPGKPGRPGERGVPGPQGARGFPGTPGLPGFKGIRGHNGLDGLTGQPGAPGVKGEPGAPGENGTPGQKGARGLPGERGRVGAPGPAGARGSDGSVGPVGPAGPIGSAGPPGFPGAPGPKGELGPVGNPGPAGPAGPRGEVGLPGLSGPVGPPGNAGPNGLPGAKGAAGLPGVAGAPGLPGPRGIPGPVGAAGATGARGLVGEPGPAGSKGESGNKGEPGAVGQPGPPGPSGEEGKRGSTGEIGPAGPPGPPGLRGNPGSRGLPGADGVAGVMGPAGSRGTSGPAGVRGPNGDSGRPGEPGLMGPRGFPGSPGNIGPAGKEGPVGLPGIDGRPGPIGPAGPRGEAGAIGFPGPKGPTGEPGKPGEKGNVGLAGARGAPGPDGNNGAQGPPGLQGVQGEKGEQGPAGPPGFQGLPGPAGPAGEAGKPGERGLHGEFGLPGPAGARGERGPPGERGAAGPTGPIGSRGPSGPPGPDGNKGEAGAVGPAGAPGPAGPPGIPGERGVAGVPGGKGEKGAPGLRGDTGATGRDGARGLPGAIGAPGPAGGAGDRGEGGPAGPAGPAGARGIRGERGEPGPVGPSGFAGPAGAAGQPGAKGERGTKGPVGEQGPVGPQGPVGAAGPPGPVGAAGPAGPRGDAGPTGMTGFPGAAGRTGPPGPSGLTGPPGPPGAAGKEGIRGPRGDQGPVGRSGETGATGPTGFVGEKGPTGEPGSAGPPGPPGPQGLLGAPGFLGLPGSRGERGLPGVAGSVGEPGPLGIAGPPGARGPPGNVGNPGVNGAPGEAGRDGNPGNDGPPGRDGQPGHKGERGTPGNAGPPGAVGPVGPVGEPGKLGNRGEPGPAGAVGPAGAVGPRGPSGPQGIRGDDGEPGDKGDKGIKGDRGHNGLQGLPGLAGHHGDQGAPGAVGPAGPRGPAGPSGPAGKIGRIGAVGPAGAAGIRGSQGSQGPAGPPGPPGPPGPPGPPSGGYEF/C:EMSYGYDEKSTGISVPGPMGPSGPRGLPGPPGAPGPQGFQGPPGEPGEPGASGPMGPRGPPGPPGKNGDDGEAGKPGRPGERGPPGPQGARGLPGTAGLPGMKGHRGFSGLDGAKGDAGPAGPKGEPGSPGENGAPGQMGPRGLPGERGRPGAPGPAGARGNDGAAGAAGPPGPTGPTGPPGFPGAVGAKGEAGPEGARGSEGPQGVRGEPGPPGPAGAAGPAGNPGADGQPGAKGANGAPGIAGAPGFPGARGPSGPEGPSGAPGPKGNSGEPGAPGNKGDTGAKGEPGPAGVQGPPGPAGEEGKRGARGEPGPSGLPGPPGERGGPGSRGFPGADGVAGPKGPAGERGSPGPAGPKGSPGEAGRPGEAGLPGAKGLTGSPGSPGPDGKTGPPGPAGEDGRPGPAGPPGARGQAGVMGFPGPKGAAGEPGKAGERGVPGPPGAVGPAGKDGEAGAQGPPGPAGPAGERGEQGPAGSPGFQGLPGPAGPPGEAGKPGEQGVPGDLGAPGPSGARGERGFPGERGVEGPPGPAGPRGANGAPGNDGAKGDAGAPGAPGSQGAPGLQGMPGERGAAGLPGPKGDRGDAGPKGADGAPGKDGVRGLTGPIGPPGPAGAPGDKGEAGPSGPAGPTGARGAPGDRGEPGPPGPAGFAGPPGADGQPGAKGEPGDAGAKGDAGPPGPAGPAGPPGPIGNVGAPGPKGARGSAGPPGATGFPGAAGRVGPPGPSGNAGPPGPPGPAGKEGSKGPRGETGPAGRPGEVGPPGPPGPAGEKGAPGADGPAGAPGTPGPQGIAGQRGVVGLPGQRGERGFPGLPGPSGEPGKQGPSGASGERGPPGPMGPPGLAGPPGESGREGAPGAEGSPGRDGSPGAKGDRGETGPAGPPGAPGAPGAPGPVGPAGKSGDRGETGPAGPIGPVGPAGARGPAGPQGPRGDKGETGEEGDRGIKGHRGFSGLQGPPGPPGSPGEQGPSGASGPAGPRGPPGSAGSPGKDGLNGLPGPIGPPGPRGRTGDAGPAGPPGPPGPPGPPGPPSGGYDLSFLPQPPQQKAHDKGRYY
Sequence Assay Result Units