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Sequential assembly of collagen revealed by atomic force microscopy
M Gale1, M S Pollanen, P Markiewicz
1Department of Chemistry, University of Toronto, Ontario, Canada.
Biophysical Journal
|May 1, 1995
Summary
Atomic force microscopy revealed collagen assembly intermediates. Collagen monomers form oligomers via end-to-end association, followed by lateral association into higher-order filaments.
Area of Science:
- Biochemistry
- Biophysics
- Materials Science
Background:
- Biological filament assembly typically follows nucleation-elongation or stepwise mechanisms.
- Understanding intermediate species is crucial for elucidating complex assembly processes.
Purpose of the Study:
- To investigate the early events in the sequential assembly of collagen filaments using atomic force microscopy (AFM).
- To correlate structural intermediates observed by AFM with turbidimetric changes during collagen assembly.
Main Methods:
- In vitro assembly of collagen monomers.
- Examination of early structural intermediates using Atomic Force Microscopy (AFM).
- Correlation of AFM observations with turbidimetric measurements.
Main Results:
- Observed sequential formation of collagenous filamentous species with increasing diameter and length.
- Identified initial collagen oligomers (1-2 nm diameter, 300-500 nm length).
- Detected larger filaments (2-6 nm diameter, >10 microns length) with a ~67 nm axial period, and mature fibrils later in assembly.
Conclusions:
- Collagen assembly involves initial end-to-end monomer association to form oligomers.
- Subsequent lateral association of oligomers leads to higher-order filaments.
- Distinct axial and lateral interactions govern different levels of the collagen assembly hierarchy.