Issue 35, 2018

Two dimensional crowding effects on protein folding at interfaces observed by chiral vibrational sum frequency generation spectroscopy

Abstract

The crowding effect is prevalent in cellular environments due to high concentrations of biomacromolecules. It can alter the structures and dynamics of proteins and thus impact protein functions. The crowding effect is important not only in 3-dimensional cytoplasm but also for a 2-dimensional (2D) cell surface due to the presence of membrane proteins and glycosylation of membrane proteins and phospholipids. These proteins and phospholipids – with limited translational degrees of freedom along the surface normal – are confined in 2D space. Although the crowding effect at interfaces has been studied by adding crowding agents to bulk solution, the 2D crowding effect remains largely unexplored. This is mostly due to challenges in controlling 2D crowding and synergistic use of physical methods for in situ protein characterization. To address these challenges, we applied chiral vibrational sum frequency generation (SFG) spectroscopy to probe the sp1 zinc finger (ZnF), a 31-amino acid protein, folding into a β-hairpin/α-helix (ββα) motif upon binding to Zn2+. We anchored ZnF at the air/water interface via covalent linkage of ZnF to palmitic acid and controlled 2D crowding by introducing neutral lipid as a spacer. We obtained chiral amide I SFG spectra upon addition of Zn2+ and/or spacer lipid. The chiral SFG spectra show that interfacial crowding in the absence of spacer lipid hinders ZnF from folding into the ββα structure even in the presence of Zn2+. The results establish a paradigm for future quantitative, systematic studies of interfacial crowding effects.

Graphical abstract: Two dimensional crowding effects on protein folding at interfaces observed by chiral vibrational sum frequency generation spectroscopy

Supplementary files

Article information

Article type
Communication
Submitted
17 10 2017
Accepted
17 8 2018
First published
17 8 2018

Phys. Chem. Chem. Phys., 2018,20, 22421-22426

Author version available

Two dimensional crowding effects on protein folding at interfaces observed by chiral vibrational sum frequency generation spectroscopy

W. Liu, L. Fu, Z. Wang, Z. Sohrabpour, X. Li, Y. Liu, H. Wang and E. C. Y. Yan, Phys. Chem. Chem. Phys., 2018, 20, 22421 DOI: 10.1039/C7CP07061F

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements