Measuring the Multiscale Dynamics, Structure, and Function of Biomolecules at Interfaces

Abstract

The individual and collective structure and properties of biomolecules can change dramatically when they are localized at an interface. However, the small spatial extent of interfacial regions poses challenges to the detailed characterization of multiscale processes that dictate the structure and function of large biological units such as peptides, proteins, or nucleic acids. This Perspective surveys a broad set of tools that provide new opportunities to probe complex, dynamic interfaces across the vast range of temporal regimes that connect molecular-scale events to macroscopic observables. An emphasis is placed on the integration over multiple time scales, the use of complementary techniques, and the incorporation of external stimuli to control interfacial properties with spatial, temporal, and chemical specificity.

Measuring Protein Conformation at Aqueous Interfaces with 2D Infrared Spectroscopy of Emulsions

“…Many solvated proteins radically change their conformations at aqueous interfaces, thanks to the interplay of hydrophobic and hydrophilic residues with surfaces . As much of chemistry and biology occurs at these interfaces, understanding protein structure at them is vital. − One of the most powerful techniques for measuring secondary and tertiary structure of proteins is two-dimensional infrared (2D-IR) spectroscopya third-order nonlinear spectroscopy that reveals spectral correlations and allows dynamics to be tracked with femtosecond resolution. − However, like linear IR spectroscopy, 2D-IR is not a surface specific technique, and so the samples or experimental geometry must be very carefully designed to minimize bulk contributions . Typically this involves immobilizing a monolayer of analyte to a solid substrate, which prevents measurements at liquid/liquid or liquid/gas interfaces, although reflection 2D-IR of an organometallic surfactant monolayer at the air/water interface has also been demonstrated …”

Electrostatic modulation of multiple binding events between loquacious-PD and double-stranded RNA

“…Interrogating the binding mechanism of complex biomolecules from a molecular perspective that accounts for their local environment requires a multi-pronged approach. 7 One way to achieve these goals is to combine time-resolved fluorescence and surface plasmon resonance measurements on functionalized transparent electrodes, 8 a multimodal approach that incorporates distinct observables to yield complementary information while introducing a controllable local electrostatic perturbation to the interactions between binding partners -vs. bulk perturbations to dielectric screening. 9 Importantly, a bifunctional silane self-assembled monolayer localizes the formation of biomolecular complexes to an electrified interface with generalizable surface functionalization protocols.…”

Dynamic Response of Surface‐Bound Peptides to a pH Perturbation Under Controlled Electrostatic Conditions

“…If the functional macromolecules reside at an interface, their characterization is further complicated by the need for interfacial sensitivity and/or selectivity coupled with appropriate temporal resolution and compatibility with the incorporation of controllable external DOI: 10.1002/marc.202200635 stimuli. [15] When measuring the transformations of complex macromolecules localized at an interface, the detection of complementary observables is critical to distinguishing signals that arise from concurrent processes (e.g., concerted binding and folding events) or from distinct sub-populations (e.g., buried and solvent-exposed polymer segments). Indeed, the value of collecting complementary observables is highlighted when the effects due to multiple simultaneous stimuli are of interest.…”