Related Experiment Video

Updated: Aug 12, 2026

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

Conformational features of bradykinin. A circular dichroism study of the aromatic side-chains

K Lintner, S Fermandjian, D Regoli

    European Journal of Biochemistry
    |December 1, 1977
    PubMed

    More Related Videos

    Investigating Protein Sequence-structure-dynamics Relationships with Bio3D-web09:51

    Investigating Protein Sequence-structure-dynamics Relationships with Bio3D-web

    Published on: July 16, 2017

    Characterization of pH-Dependent Reversible Self-Assembly of Amyloid Beta 1-40-Coated Gold Colloids08:53

    Characterization of pH-Dependent Reversible Self-Assembly of Amyloid Beta 1-40-Coated Gold Colloids

    Published on: March 21, 2025

    Related Concept Videos

    Conformations of Cyclohexane02:11

    Conformations of Cyclohexane

    Cyclohexane does not exist in a planar form due to the high angle and torsional strain it would experience in the planar structure. Instead, it adopts non-planar chair and boat conformations.
    The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
    Chair Conformation of Cyclohexane02:02

    Chair Conformation of Cyclohexane

    The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
    The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
    ¹H NMR of Conformationally Flexible Molecules: Temporal Resolution00:52

    ¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

    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...
    Aromatic Hydrocarbon Anions: Structural Overview01:18

    Aromatic Hydrocarbon Anions: Structural Overview

    Neutral hydrocarbons like cyclopentadiene with an odd number of carbon atoms and one intervening CH2 group in the ring are not aromatic. Cyclopentadiene with 4 π electrons does not satisfy the 4n + 2 π electron rule. Additionally, the intervening CH2 group is sp3 hybridized and lacks a vacant p orbital, thereby interrupting the overlap of p orbitals in a continuous manner and preventing the delocalization of π electrons throughout the ring.
    Due to the absence of continuous overlap of p...
    π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds01:14

    π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds

    In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as annulenes. In...
    ¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR01:15

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

    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.