Calcium Destabilizes and Causes Conformational Changes in Hyaluronic Acid

The physical properties of proteoglycans found in the extracellular matrix influence the behavior of resident macromolecules, micro-ions, and cells. The forces stabilizing structured regions of hyaluronic acid (HA), a major component of extracellular matrix, were measured. The free energy of stabili...

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Bibliographic Details
Published in:The American journal of the medical sciences 1989-07, Vol.298 (1), p.8-14
Main Authors: Gabriel, Don A., Carr, Marcus E.
Format: Article
Language:English
Subjects:
Analytical, structural and metabolic biochemistry
Biological and medical sciences
Calcium
Calcium - pharmacology
Carbohydrates
Fundamental and applied biological sciences. Psychology
Humans
Hyaluronic Acid
Light
Molecular Conformation
Other biological molecules
Potentiometry
Scattering, Radiation
Secondary structure
Viscosity
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Summary:The physical properties of proteoglycans found in the extracellular matrix influence the behavior of resident macromolecules, micro-ions, and cells. The forces stabilizing structured regions of hyaluronic acid (HA), a major component of extracellular matrix, were measured. The free energy of stability associated with structured regions within human HA was determined by potentiometric titration. A plot of free energy versus temperature demonstrated that the secondary structure was most stable at 25° C and was destabilized at temperatures near 50° C. In the presence of 5 mM CaCl2, the free energy of stability of the structured regions was reduced by 30 cal/mole. Classical light scattering and viscosity measurements confirmed the impact of calcium on HA. CaCl2 (5 mM) reduced the radius of gyration of HA. Above concentrations of 3 mM calcium, the viscosity of 0.1% HA solutions was reduced sharply. The ability of cells to secrete calcium, combined with the exquisite sensitivity of HA to calcium, may permit cell-mediated modification of the extracellular matrix and thus may facilitate cell motility.
ISSN:0002-9629
1538-2990
DOI:10.1097/00000441-198907000-00002