# Thrombin-derived C-terminal peptides bind and form aggregates with sulfated glycosaminoglycans

## TL;DR

This study shows that thrombin-derived peptides form aggregates with sulfated glycosaminoglycans, which may influence inflammation and wound healing.

## Contribution

The novel finding is that 11 kDa thrombin-derived peptides adopt β-sheet structures and aggregate with GAGs through electrostatic interactions.

## Key findings

- 11 kDa thrombin-derived peptides aggregate with sulfated glycosaminoglycans like heparin and heparan sulfate.
- Circular dichroism and ThT fluorescence confirm β-sheet formation in the presence of GAGs.
- In silico simulations reveal electrostatic interactions dominate between peptides and GAGs.

## Abstract

Glycosaminoglycans (GAGs) such as heparin and heparan sulfate (HS) play crucial roles in inflammation and wound healing, serving as regulators of growth factors and pro-inflammatory mediators. In this study, we investigated the influence of heparin/HS on thrombin proteolysis and its interaction with the generated 11 kDa thrombin-derived C-terminal peptides (TCPs). Employing various biochemical and biophysical methods, we demonstrated that 11 kDa TCPs aggregate in the presence of GAGs, including heparin, heparan sulfate, and chondroitin sulfate-B. Circular dichroism analysis demonstrated that 11 kDa TCPs, in the presence of GAGs, adopt a β-sheet structure, a finding supported by thioflavin T1 (ThT) fluorescence measurements and visualization of 11 kDa TCP-heparin complexes using transmission electron microscopy (TEM). Furthermore, our investigations revealed a stronger binding affinity between 11 kDa TCPs and GAGs with higher sulfate group contents. Congruently, in silico simulations showed that interactions between 11 kDa TCPs and heparin/HS are predominantly electrostatic in nature. Collectively, our study suggests that 11 kDa TCPs have the capacity to aggregate in the presence of GAGs, shedding light on their potential roles in inflammation and wound healing.

Image 1