Stabilization and Anomalous Hydration of Collagen Fibril under Heating
Open Access
- 11 November 2013
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 8 (11), e78526
- https://doi.org/10.1371/journal.pone.0078526
Abstract
Type I collagen is the most common protein among higher vertebrates. It forms the basis of fibrous connective tissues (tendon, chord, skin, bones) and ensures mechanical stability and strength of these tissues. It is known, however, that separate triple-helical collagen macromolecules are unstable at physiological temperatures. We want to understand the mechanism of collagen stability at the intermolecular level. To this end, we study the collagen fibril, an intermediate level in the collagen hierarchy between triple-helical macromolecule and tendon. When heating a native fibril sample, its Young’s modulus decreases in temperature range 20–58°C due to partial denaturation of triple-helices, but it is approximately constant at 58–75°C, because of stabilization by inter-molecular interactions. The stabilization temperature range 58–75°C has two further important features: here the fibril absorbs water under heating and the internal friction displays a peak. We relate these experimental findings to restructuring of collagen triple-helices in fibril. A theoretical description of the experimental results is provided via a generalization of the standard Zimm-Bragg model for the helix-coil transition. It takes into account intermolecular interactions of collagen triple-helices in fibril and describes water adsorption via the Langmuir mechanism. We uncovered an inter-molecular mechanism that stabilizes the fibril made of unstable collagen macromolecules. This mechanism can be relevant for explaining stability of collagen.Keywords
This publication has 52 references indexed in Scilit:
- Theory for Protein Folding Cooperativity: Helix BundlesJournal of the American Chemical Society, 2009
- Water as an Active Constituent in Cell BiologyChemical Reviews, 2007
- Thermodynamic and structural characteristics of collagen fibrils formed in vitro at different temperatures and concentrationsBiophysics, 2007
- Nature designs tough collagen: Explaining the nanostructure of collagen fibrilsProceedings of the National Academy of Sciences of the United States of America, 2006
- A microcalorimetric study of collagen hydration in the temperature range 20–100°C by measuring the enthalpy of water evaporation from sampleBiophysics, 2006
- The Kinetics of the Thermal Denaturation of Collagen in Unrestrained Rat Tail Tendon Determined by Differential Scanning CalorimetryJournal of Molecular Biology, 1995
- Theory of helix-coil transitions of .alpha.-helical, two-chain, coiled coilsMacromolecules, 1982
- A statistical mechanical study of helix-coil transition in concentrated solutions of polypeptides and proteinsPeptide Science, 1974
- Calorimetry of rat tail tendon collagen before and after denaturation: the heat of fusion of its absorbed waterPeptide Science, 1971
- Adsorption of Water Vapor by Proteins1Journal of the American Chemical Society, 1944