Faculty Opinions recommendation of Polymer scaling laws of unfolded and intrinsically disordered proteins quantified with single-molecule spectroscopy.

Author(s):  
Devarajan Thirumalai
Biomolecules ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1756
Author(s):  
Xuchang Su ◽  
Zhi He ◽  
Lijun Meng ◽  
Hong Liang ◽  
Ruhong Zhou

Single-molecule techniques such as electron tunneling and atomic force microscopy have attracted growing interests in protein sequencing. For these methods, it is critical to refine and stabilize the protein sample to a “suitable mode” before applying a high-fidelity measurement. Here, we show that a planar heterostructure comprising boronic graphene (BC3) and nitrogenized graphene (C3N) sandwiched stripe (BC3/C3N/BC3) is capable of the effective stretching and confinement of three types of intrinsically disordered proteins (IDPs), including amyloid-β (1–42), polyglutamine (Q42), and α-Synuclein (61–95). Our molecular dynamics simulations demonstrate that the protein molecules interact more strongly with the C3N stripe than the BC3 one, which leads to their capture, elongation, and confinement along the center C3N stripe of the heterostructure. The conformational fluctuations of IDPs are substantially reduced after being stretched. This design may serve as a platform for single-molecule protein analysis with reduced thermal noise.


2021 ◽  
Author(s):  
Pétur O. Heidarsson ◽  
Ciro Cecconi

Abstract Single-molecule manipulation with optical tweezers has uncovered macromolecular behaviour hidden to other experimental techniques. Recent instrumental improvements have made it possible to expand the range of systems accessible to optical tweezers. Beyond focusing on the folding and structural changes of isolated single molecules, optical tweezers studies have evolved into unraveling the basic principles of complex molecular processes such as co-translational folding on the ribosome, kinase activation dynamics, ligand–receptor binding, chaperone-assisted protein folding, and even dynamics of intrinsically disordered proteins (IDPs). In this mini-review, we illustrate the methodological principles of optical tweezers before highlighting recent advances in studying complex protein conformational dynamics – from protein synthesis to physiological function – as well as emerging future issues that are beginning to be addressed with novel approaches.


2020 ◽  
Vol 118 (3) ◽  
pp. 214a
Author(s):  
Saurabh Awasthi ◽  
Jared Houghtaling ◽  
Cuifeng Ying ◽  
Aziz Fennouri ◽  
Ivan Shorubalko ◽  
...  

2013 ◽  
Vol 85 (4) ◽  
pp. 2449-2456 ◽  
Author(s):  
Deanpen Japrung ◽  
Jakob Dogan ◽  
Kevin J. Freedman ◽  
Achim Nadzeyka ◽  
Sven Bauerdick ◽  
...  

2020 ◽  
Author(s):  
Franziska Zosel ◽  
Andrea Holla ◽  
Benjamin Schuler

Single-molecule fluorescence spectroscopy has become an important technique for studying the conformational dynamics and folding of proteins. A key step for performing such experiments is the availability of high-quality samples. Here we describe the practical details of a simple and widely applicable strategy for preparing proteins that are site-specifically labeled with a donor and an acceptor dye for single-molecule Förster resonance energy transfer (FRET) experiments. The method is based on introducing two cysteine residues that are labeled with maleimide-functionalized fluorophores, combined with high-resolution chromatography. We discuss how to optimize site-specific labeling even in the absence of orthogonal coupling chemistry and present purification strategies that are suitable for samples ranging from intrinsically disordered proteins to large folded proteins. We also discuss common problems in protein labeling, how to avoid them, and how to stringently control sample quality.<br>


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