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Two collagen-binding domains of vitronectin
M Ishikawa-Sakurai1, M Hayashi
1Department of Biology, Ochanomizu University, Tokyo, Japan.
Cell Structure and Function
|August 1, 1993
Summary
Researchers identified two distinct collagen-binding sites on vitronectin, a key glycoprotein. This finding clarifies molecular interactions within the extracellular matrix and animal blood, crucial for cell adhesion.
Area of Science:
- Biochemistry
- Molecular Biology
- Cell Biology
Background:
- Vitronectin is a cell-adhesive glycoprotein found in animal blood and extracellular matrix.
- Understanding vitronectin's interactions with extracellular matrix macromolecules is essential for elucidating its biological functions.
Purpose of the Study:
- To investigate the molecular basis of vitronectin's binding interactions with collagen.
- To identify the specific collagen-binding sites within the vitronectin molecule.
Main Methods:
- Vitronectin was cleaved using formic acid to generate fragments.
- Fragments were separated using heparin-affinity chromatography and gel filtration chromatography.
- Collagen-binding activity was assessed by measuring the inhibition of 125I-vitronectin binding to immobilized collagen.
Main Results:
- Two groups of collagen-binding vitronectin fragments were identified.
- One group comprised five heparin-binding fragments (12-19 kDa).
- The second group included two heparin-nonbinding fragments (18 kDa and 40 kDa), indicating distinct binding domains.
Conclusions:
- Vitronectin possesses at least two distinct collagen-binding sites.
- One site is located near the heparin-binding domain in the COOH-terminal half.
- The second site is situated in the NH2-terminal half of the vitronectin molecule.