The nanomechanics of individual proteins

Abstract

This tutorial review provides an overview of the single protein force spectroscopy field, including the main techniques and the basic tools for analysing the data obtained from the single molecule experiments.

Magnetic tweezers meets AFM: ultra-stable protein dynamics across the force spectrum

“…Single-molecule force spectroscopy techniques have enabled to manipulate single molecules and have revolutionized our understanding of protein dynamics. AFM, optical tweezers, or magnetic tweezers have permitted to delve into this topic and have provided a wealth of information 6 . From these studies, we know now that while some proteins undergo dramatic conformational changes within less than 1 pN 22,24,25 , some other proteins or protein-protein interactions unfold or break when exposed to hundreds of pN 17 , and only fold or reform at very low mechanical loads.…”

“…For more than 20 years, single-molecule force spectroscopy techniques have enabled the mechanical manipulation of proteins and provided us insightful views of mechanobiological processes at the nanoscale 6 . Atomic Force Microscopy (AFM), one of the first techniques developed and yet today among the most used ones, can apply well-calibrated forces to single proteins over a range that spans from 10 pN to 2000 pN 7,8 .…”

Protein nanomechanics: The power of stretching

“…During the past two decades, an impressive body of literature has unravelled the basic rules governing protein (un)folding under force [2]. The first implication of using force (a vectorial quantity) as a denaturant is that it distributes non-isotropically throughout the protein backbone.…”

Identical Sequences, Different Behaviors: Protein Diversity Captured at the Single-Molecule Level

“…In this context, the emergence of single-molecule force spectroscopy techniques shifted the paradigm of biophysical experimentation by allowing to interrogate individual molecules under force to directly sample the distributions of their molecular properties without relying on pre-averaged signals. 9,10 While protein nanomechanics has been typically approached using atomic force miscroscopy (AFM) and optical tweezers, these two techniques suffer from large mechanical drift that limits the measurements to a few minutes, eventually requiring to interrogate several molecular samples to accumulate enough statistics. 11,12 By contrast, magnetic tweezers, an intrinsically more stable technique, has been mostly devoted to the study of nucleic acids, likely owing to the lower temporal and spatial resolution of the early instrumental designs, and the initial difficulty to obtain specific and long lasting tethers.…”

“…11,12 By contrast, magnetic tweezers, an intrinsically more stable technique, has been mostly devoted to the study of nucleic acids, likely owing to the lower temporal and spatial resolution of the early instrumental designs, and the initial difficulty to obtain specific and long lasting tethers. 10,12–16 However, recent instrumental advances and the development of novel anchoring strategies are now demonstrating the expediency of magnetic tweezers for measuring protein mechanics. 17–20 Magnetic tweezers have the crucial advantage of offering intrinsic force-clamp conditions, which afford direct control of the intensive variable (force), while the extensive variable (extension) is measured, providing the natural statistical ensemble for studying protein dynamics in equilibrium.…”