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Structural Characterization of Covalently Stabilized Human Cystatin C Oligomers
Magdalena Chrabąszczewska1,2, Adam K Sieradzan3, Sylwia Rodziewicz-Motowidło3
1Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland.
International Journal of Molecular Sciences
|August 23, 2020
Summary
Human cystatin C (HCC) can form stable, doughnut-shaped oligomers. This study models these structures, revealing dimensions crucial for understanding protein misfolding diseases.
Area of Science:
- Biochemistry
- Structural Biology
- Biophysics
Background:
- Human cystatin C (HCC) is a cysteine-protease inhibitor.
- Under physiological conditions, HCC exists as a folded monomer.
- HCC can self-assemble into multimeric states, including doughnut-like oligomers, via domain swapping.
Purpose of the Study:
- To characterize the structure of stabilized HCC oligomers (stab-1 HCC).
- To develop a structural model for dodecameric stab-1 HCC oligomers.
- To provide insights into the structural relevance of HCC oligomers in protein misfolding diseases.
Main Methods:
- Molecular modeling and simulations.
- Atomic Force Microscopy (AFM).
- Transmission Electron Microscopy (TEM).
- Small-Angle X-ray Scattering (SAXS).
Main Results:
- Stabilized HCC (stab-1 HCC) forms stable oligomers of 10-12 subunits.
- Oligomers are flat, approximately 2 nm in height.
- The diameter from the outer ring edge to the central cavity edge is ~5.1 nm.
- A dodecamer model for stab-1 HCC oligomers was developed using molecular dynamics and experimental data.
Conclusions:
- The characterized stab-1 HCC oligomers exhibit specific dimensions corresponding to monomeric subunit height and diameter.
- The structural data on isolated stab-1 HCC oligomers can aid in investigating the physiological role of different HCC species in protein misfolding.
- This research contributes to understanding the structural basis of cystatin C aggregation and its link to disease.
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