PhD Scientific Days 2020

Theoretical and Translational II. Posters

Von Willebrand Multimer Structure and Extensibility Analyzed by Single-molecule AFM

Előadó neve

Csanyi, Csilla

Előadó munkahelye

Department of Biophysics and Radiation Biology, Semmelweis University, Budapest

Előadó telefonszáma

+36306161538

Előadó e-mail címe

csanyicsilla90@gmail.com

Az előadás címe

Von Willebrand Multimer Structure and Extensibility Analyzed by Single-molecule AFM

Szerző(k) neve és munkahelye

Csilla Csanyi1, Pal Salamon2, Timea Feller1, Miklos Kellermayer1, Jolan Harsfalvi1
1Department of Biophysics and Radiation Biology, Semmelweis University, Budapest
2 Department of Bioengineering, Sapientia Hungarian University of Transylvania, Csikszereda

Szekció

Theoretical and Translational II. Posters

Language of the presentation

Hungarian

Section, first choice

Theoretical and Translational Medicine

Section, second choice

Molecular Sciences

Összefoglaló szövege

Von Willebrand factor (VWF) is a multimeric glycoprotein of 1-24 homodimer molecules. The extended multimers are cofactors of platelet adhesion at high shear in a size-dependent manner. The size of the multimers is tightly regulated to prevent bleeding or thrombotic events. Based on electron microscopic analyses, dimers within the multimer consist of two large globules and a small one which correspond to the N- and C- termini, respectively. The globules are connected via flexible, rod-like structures. The distance between of the two large globules is 120 nm uniformly. Based on atomic force microscopic (AFM) analyses these distances are 80-100 nm and the relative extension of multimers depends on the number of the component dimers.
In order to uncover whether the extension of a VWF multimer depends only on the number of the component dimers, or the dimers might also become extended, we analysed the axial structure of the multimers by employing high-resolution single-molecule techniques.
We purified plasma-derived VWF multimers with heparin affinity chromatography and investigated their topographical structure with AFM. Samples were diluted to 1 ng/µl in PBS pH7.4 containing 50% glycerol and dropped on mica either incubated for 1 min or immediately extended by molecular combing with receding meniscus (13000 rpm for 10s), washed and dried. Igor Pro 6/AR14 was used to analyse images.
The contour length of the elongated multimeric molecules varied between 126 and 2650 nm. As expected, the contour length increased with the number of dimers in the chain. However, it was longer than calculated by the known length of dimers. The median length of dimers also increased, from 13 nm to 294 nm, and correlated with the contour length (r=0.73 (p<0.0001, n=68). The number of small globules between the dimers varied from 0 to 3 depending on the extension.
We conclude that the variation in the extension and structure of the dimers within the multimer explain the size-dependent function of VWF multimers. The large number of component dimers and their extended state, which appear to be a hallmarks of multimeric VWF, provide large local binding-site concentration and conformational accessibility, respectively, for platelet adhesion. The single-molecule approach employed here thus sheds light on the size-dependent diversity in the haemostatic role of VWF.

Additional Information

Doctoral School: Basic and Translational Medicine
Program: Cellular and Molecular Biophysics
Supervisor: Jolan Harsfalvi

Bemutatás módja

Poszter

Kind

Szabad

Status

elfogadva

Accepted presentation method

poszter

Előadás fájl jóváhagyás

nem rendelkezett róla

Előadó

1305

Start

12:59

End

13:02

Authors (legacy)

Csilla Csanyi1, Pal Salamon2, Timea Feller1, Miklos Kellermayer1, Jolan Harsfalvi1
1Department of Biophysics and Radiation Biology, Semmelweis University, Budapest
2 Department of Bioengineering, Sapientia Hungarian University of Transylvania, Csikszereda