On the lipid-bacterial protein interaction studied by quartz crystal microbalance with dissipation, transmission electron microscopy and atomic force microscopy

TL;DR

This study investigates how bacterial S-protein SbpA interacts with various lipid membranes using multiple microscopy and sensing techniques, revealing specific conditions for nanocrystal formation and protein adsorption.

Contribution

It provides detailed insights into the lipid-dependent behavior of SbpA protein interactions, combining advanced microscopy with quartz crystal microbalance measurements.

Findings

SbpA forms nanocrystals on certain lipid bilayers and monolayers.

SbpA adsorbs on specific zwitterionic and charged lipid membranes.

No adsorption or recrystallization occurs on some lipid types.

Abstract

The interaction between the bacterial S-protein SbpA on different types of lipid membranes has been studied using atomic force microscopy, transmission electron microscopy, and quartz crystal microbalance with dissipation. On one hand, It has been found that the bacterial forms two dimensional nanocrystals on zwitterionic DOPC bilayers and negatively charged DMPG vesicles adsorbed on mica, on zwitterionic DPPC and charged DPPC/DMPG (1:1) monolayers adsorbed on carbon grids. On the other hand, SbpA protein adsorption took place on zwitterionic DOPC bilayers and DOPC/DOPS (4:1) bilayers, previously adsorbed on silicon supports. SbpA adsorption also took place on DPPC/DOPS (1:1) monolayers adsorbed on carbon grids. Finally, neither SbpA adsorption, nor recrystallization was observed on zwitterionic DMPC vesicles (previously adsorbed on polyelectrolyte multilayers), and on DPPC vesicles supported on silicon.