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Single-Molecule Unbinding Forces between the Polysaccharide Hyaluronan and Its Binding Proteins.
Fouzia Bano1, Markku I Tammi2, David W Kang3
1School of Biomedical Sciences, Faculty of Biological Sciences, School of Physics and Astronomy, Faculty of Mathematics and Physical Sciences, and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom; CIC biomaGUNE, Biosurfaces Laboratory, Donostia-San Sebastian, Spain.
Biophysical Journal
|June 21, 2018
Summary
Hyaluronan (HA) binding proteins (hyaladherins) form crucial tissue complexes. Mechanical stress reveals that longer HA-binding domains, like aggrecan and link protein, create stronger bonds than shorter ones, impacting tissue mechanics.
Area of Science:
- Biophysics
- Biochemistry
- Extracellular Matrix Biology
Background:
- Hyaluronan (HA) is a vital extracellular polysaccharide in vertebrate tissues.
- HA forms supramolecular complexes with HA-binding proteins (hyaladherins).
- The mechanical stability of HA-hyaladherin bonds under stress is largely unknown.
Purpose of the Study:
- To analyze and compare the mechanical strength of bonds between HA and various hyaladherins.
- To investigate how the size of the HA-binding domain influences bond strength.
- To understand the implications for the mechanical properties of HA-rich extracellular matrices.
Main Methods:
- Utilized a single-molecule force spectroscopy platform.
- Analyzed the mechanical resistance of HA bonds with a panel of hyaladherins.
- Compared rupture forces across different hyaladherin types and HA-binding domain sizes.
Main Results:
- Hyaladherin bond strength under tensile stress correlates with HA-binding domain size.
- Shorter binding domains (TSG-6, HARE) exhibited lower mean rupture forces.
- Longer binding domains (aggrecan-link protein complex) formed bonds with mechanical stability comparable or superior to streptavidin-biotin.
Conclusions:
- The size of the HA-binding domain is a key determinant of hyaluronan-hyaladherin bond mechanical strength.
- These findings provide insights into the molecular mechanisms of HA-hyaladherin unbinding under force.
- Understanding these mechanics is crucial for comprehending the properties of HA-rich extracellular matrices.
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