Monomer and oligomer of type I collagen: molecular properties and fibril assembly
| Autor: | George C. Na |
|---|---|
| Rok vydání: | 1989 |
| Předmět: |
Isothermal microcalorimetry
Protein Denaturation Macromolecular Substances Kinetics Centrifugation macromolecular substances Fibril Biochemistry Oligomer chemistry.chemical_compound Ultraviolet visible spectroscopy Animals Organic chemistry Gel electrophoresis Calorimetry Differential Scanning Temperature Monomer chemistry Biophysics Thermodynamics Cattle Electrophoresis Polyacrylamide Gel Collagen Oxidation-Reduction Type I collagen |
| Zdroj: | Biochemistry. 28:7161-7167 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi00444a005 |
| Popis: | Type I collagen purified from calf skin was further separated into monomeric and oligomeric fractions and characterized with gel electrophoresis and measurement of solution viscosity. The thermal stabilities of the triple-helical structure of the collagen molecules of these preparations and the fibrils assembled therefrom were determined with differential UV spectroscopy and scanning microcalorimetry. The monomeric collagen was reduced with NaBH4-, and the kinetics and equilibrium of the reversible fibril assembly-disassembly were examined in detail. Fibril assembly and disassembly of the collagen induced by slow scans of temperature showed hysteresis. The assembly curve was very sharp whereas the disassembly curve was gradual. Equilibrium centrifugation showed the collagen disassembled from the fibrils to be predominantly monomers. However, unlike the unassembled collagen, the collagen disassembled from fibrils by cooling showed no lag phase in subsequent cycles of fibril assembly. The thermodynamic parameters of fibril growth were derived from a fibril disassembly curve. Fibril growth was weaker for the NaBH4-reduced monomeric collagen than the native crude collagen, perhaps due to the removal of oligomers and the changes in the molecular structure brought by the reduction. The results corroborated the strongly cooperative mechanism for the fibril assembly proposed in the preceding paper. |
| Databáze: | OpenAIRE |
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