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Collagen triple helix formation can be nucleated at either end
Sabine Frank1, Sergei Boudko, Kazunori Mizuno
1Department of Biophysical Chemistry, Biozentrum, Universität Basel, Switzerland.
The Journal of Biological Chemistry
|January 24, 2003
Summary
Collagen triple helix folding can initiate from either end, challenging previous assumptions. Folding rates are independent of nucleation site, with cis-trans isomerization as the rate-limiting step.
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Biophysics
Background:
- Directional folding rates of rod-like macromolecules like collagen are under-explored due to measurement challenges.
- Collagens typically nucleate from COOH-terminal non-collagenous domains, implying COOH to NH(2) terminus folding direction.
- Understanding folding mechanisms is crucial for protein engineering and disease research.
Purpose of the Study:
- To investigate the directional dependence of collagen triple helix folding rates.
- To determine if nucleation can occur at both NH(2) and COOH termini of collagen peptides.
- To identify factors influencing triple-helical stability and folding kinetics.
Main Methods:
- Engineered proteins with collagen-like peptides fused to nucleation domains (T4-phage foldon or type III collagen disulfide knot).
- Nucleation site manipulation at either the NH(2) or COOH terminus.
- Analysis of triple-helical stability and folding rates.
Main Results:
- Effective nucleation of triple helix formation was achieved at both NH(2) and COOH termini.
- Nucleation site location influenced triple-helical stability, potentially due to linker sequences and terminal charges.
- Folding rates were independent of the nucleation site.
Conclusions:
- Collagen triple helix folding is not restricted to a single direction and can be initiated from either end.
- Cis-trans isomerization is the rate-limiting step in triple helical folding.
- Designed nucleation domains enable flexible control over collagen folding initiation.