Structural Characterization of Covalently Stabilized Human Cystatin C Oligomers

International Journal of Molecular Sciences

JanetR. Kumita¹  ChristopherM. Dobson¹  Anders Grubb²  Maciej Kozak³  Magdalena Chrabąszczewska³  AdamK. Sieradzan⁴  Sylwia Rodziewicz-Motowidło⁴ 

[1] Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK;Department of Clinical Chemistry, Lund University Hospital, S-22185 Lund, Sweden;Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland;Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland;

关键词: cystatin C;    oligomers;    domain swapping;    protein misfolding;   

DOI  :  10.3390/ijms21165860

来源: DOAJ

【 摘 要 】

Human cystatin C (HCC), a cysteine-protease inhibitor, exists as a folded monomer under physiological conditions but has the ability to self-assemble via domain swapping into multimeric states, including oligomers with a doughnut-like structure. The structure of the monomeric HCC has been solved by X-ray crystallography, and a covalently linked version of HCC (stab-1 HCC) is able to form stable oligomeric species containing 10–12 monomeric subunits. We have performed molecular modeling, and in conjunction with experimental parameters obtained from atomic force microscopy (AFM), transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) measurements, we observe that the structures are essentially flat, with a height of about 2 nm, and the distance between the outer edge of the ring and the edge of the central cavity is ~5.1 nm. These dimensions correspond to the height and diameter of one stab-1 HCC subunit and we present a dodecamer model for stabilized cystatin C oligomers using molecular dynamics simulations and experimentally measured parameters. Given that oligomeric species in protein aggregation reactions are often transient and very highly heterogeneous, the structural information presented here on these isolated stab-1 HCC oligomers may be useful to further explore the physiological relevance of different structural species of cystatin C in relation to protein misfolding disease.

【 授权许可】

Unknown