Összes szerző

Sziklai Dominik

az alábbi absztraktok szerzői között szerepel:

Csányi Mária Csilla
Nanosurgical manipulation of extended von Willebrand factor multimers

Aug 29 - kedd

15:30 – 17:00

I. Poszterszekció

P07

Nanosurgical manipulation of extended von Willebrand factor multimers

Mária Csilla Csányi1, Dominik Sziklai1, Tímea Feller2, Jolán Hársfalvi1 and Miklós S.Z. Kellermayer1

1 Semmelweis University, Faculty of Medicine, Department of Biophysics and Radiation Biology

2 University of Leeds, Leeds Institute of Cardiovascular and Metabolic Medicine, Discovery and Translational Science Department

The von Willebrand factor (VWF) is a varying-length multimeric chain of glycoprotein dimers/protomers with distinct domain structures. Conformational response of domains upon exposure to shear- and elongational forces ensures that VWF is able to mediate platelet adhesion to and aggregation on an injured vessel wall where it is explored or immobilized from the circulation. Human plasma-derived VWF multimers stretched by molecular combing extend through a specific hierarchy of structural intermediates of protomers as we have recently shown by using atomic force microscopy (AFM) [1]. However, the full scope of local domain stabilities and extensibilities remained hidden.

To uncover these cryptic structural details, in the present work, we used an in situ nanosurgical approach to probe whether targeted domains of VWF could be further extended and unfolded. To achieve this, surface-stabilized and pre-extended VWF multimers were manipulated at distinct spatial locations with the tip of the AFM cantilever. By moving the AFM tip in a direction perpendicular to the longitudinal axis of the VWF multimer, protein loops could be pulled out of the chain, the local extension of which was assessed following the acquisition of a subsequent topographic AFM image.

The extension resulted in ruptured and non-ruptured protein loops, with and without the appearance of hairpin-like thin sections and nodules, while the adjacent domains were non-displaced. Ruptures occurred in 27% of the VWF. Extension, which is the ratio of the length of the section following and prior to manipulation was 2.7 vs. 1.6, p= 0.0001 in non-ruptured and ruptured multimers. Nanomanipulation of protomers in which all the 5 nodules are separated, resulted in a mean final length of 345±69 nm, compared to their pre-manipulation length of 168±54 nm. None of the above results correlated with the protomer’s structural hierarchy showing the main role of the adhesion of certain domains to the mica surface. The nanosurgical manipulation used here demonstrates the VWF mechanical properties at the single domain level via extending further the C1-C6 and A1-A2-A3 domains or eventually rupturing them. The observed conformational changes indicate that VWF may have a large conformational force response potential in order to fine-tune the opening up of hidden epitopes for the different functions of the VWF.

Acknowledgment

TKP2021-EGA-23

References

[1] Csányi MC, Salamon P, Feller T, Bozó T, Hársfalvi J, Kellermayer MSZ. (2023) Protein Sci 32(1):e4535.