Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution00:52

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

926
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
926
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR01:15

¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR

1.2K
The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.
1.2K
IR Spectroscopy: Molecular Vibration Overview01:24

IR Spectroscopy: Molecular Vibration Overview

3.0K
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
3.0K
IR and UV–Vis Spectroscopy of Carboxylic Acids01:28

IR and UV–Vis Spectroscopy of Carboxylic Acids

4.6K
In IR spectroscopy of carboxylic acids, the C=O bond shows a characteristic band between 1710 and 1760 cm⁻¹, and the O–H bond exhibits a broad band between 2500 and 3300 cm⁻¹.
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency,...
4.6K
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)01:20

¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)

1.2K
When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
1.2K
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration01:16

IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration

1.7K
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to...
1.7K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Microscopic structure and dynamics of interfacial water at fluorinated vs nonfluorinated surfaces-Insights from ab-initio simulations and IR spectroscopy.

The Journal of chemical physics·2026
Same author

Low-barrier hydrogen bond powers long-range radical transfer in the metal-free ribonucleotide reductase.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same author

Polyfluoroalkyl-Tagged Cell-Penetrating Peptide-Additives Enhance Intracellular Protein Delivery via Sustained Monomeric Lipid Interaction.

Angewandte Chemie (International ed. in English)·2026
Same author

Infrared nanoscopy for subcellular chemical imaging.

QRB discovery·2026
Same author

Proton-Coupled Electron Transfer in Cytochrome c Oxidase: Heme a Controls the Protonation Dynamics of E286.

Chemphyschem : a European journal of chemical physics and physical chemistry·2025
Same author

Biophysics of pH-Driven Membrane Insertion: A Review of the pHLIP Peptide.

The journal of physical chemistry. B·2025

Related Experiment Video

Updated: Sep 21, 2025

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
10:03

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

18.1K

Protein conformational changes and protonation dynamics probed by a single shot using quantum-cascade-laser-based IR

Luiz Schubert1, Pit Langner1, David Ehrenberg1

  • 1Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.

The Journal of Chemical Physics
|June 1, 2022
PubMed
Summary

Quantum cascade laser (QCL)-based infrared spectroscopy enables label-free monitoring of protein reactions. This technique allows for single-shot experiments to track protein structural changes and proton movement in real-time.

More Related Videos

Submillisecond Conformational Changes in Proteins Resolved by Photothermal Beam Deflection
10:02

Submillisecond Conformational Changes in Proteins Resolved by Photothermal Beam Deflection

Published on: February 18, 2014

9.1K
Characterizing Individual Protein Aggregates by Infrared Nanospectroscopy and Atomic Force Microscopy
12:58

Characterizing Individual Protein Aggregates by Infrared Nanospectroscopy and Atomic Force Microscopy

Published on: September 12, 2019

9.9K

Related Experiment Videos

Last Updated: Sep 21, 2025

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
10:03

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

18.1K
Submillisecond Conformational Changes in Proteins Resolved by Photothermal Beam Deflection
10:02

Submillisecond Conformational Changes in Proteins Resolved by Photothermal Beam Deflection

Published on: February 18, 2014

9.1K
Characterizing Individual Protein Aggregates by Infrared Nanospectroscopy and Atomic Force Microscopy
12:58

Characterizing Individual Protein Aggregates by Infrared Nanospectroscopy and Atomic Force Microscopy

Published on: September 12, 2019

9.9K

Area of Science:

  • Spectroscopy
  • Biophysics
  • Chemical Kinetics

Background:

  • Mid-infrared (Mid-IR) spectroscopy is a label-free method for studying protein reactions.
  • Protein conformational changes and protonation are critical to many biological processes.

Purpose of the Study:

  • To investigate protein conformational changes and protonation events using quantum-cascade-laser-based dual-comb spectroscopy.
  • To compare the efficacy of dual-comb spectroscopy with a tunable quantum cascade laser (QCL)-based scanning spectrometer for monitoring irreversible reactions.

Main Methods:

  • Utilized quantum-cascade-laser-based dual-comb spectroscopy for single-shot experiments.
  • Employed bacteriorhodopsin, a well-characterized membrane protein, as a model system.
  • Compared dual-comb spectroscopy with a homebuilt tunable QCL-based scanning spectrometer.

Main Results:

  • Demonstrated the feasibility of QCL-based infrared spectroscopy for tracing functionally relevant protein structural changes.
  • Showcased the ability to monitor proton translocations via single-shot experiments.
  • Achieved high time resolution in monitoring irreversible reactions.

Conclusions:

  • QCL-based infrared spectroscopy is a viable tool for real-time monitoring of protein dynamics.
  • The technique is suitable for studying the kinetics of irreversible reactions in biochemical transformations.
  • Single-shot experiments offer a powerful approach for investigating rapid biological processes.