Related Experiment Video
Updated: May 25, 2025
09:25
Author Spotlight: Exploring Intrinsically Disordered Protein Dynamics Through NMR Relaxation Experiments
Published on: November 1, 2024
1.7K
Phi-Value and NMR Structural Analysis of a Coupled Native-State Prolyl Isomerization and Conformational Protein
Ulrich Weininger1, Maximilian von Delbrück2, Franz X Schmid2
1Institute of Physics, Biophysics, Martin-Luther-University Halle-Wittenberg, 06120 Halle (Saale), Germany.
Biomolecules
|February 26, 2025
Summary
Protein folding involves prolyl cis/trans isomerization, a key step. This study shows early folding events in the N2 domain control this isomerization, optimizing native structure formation.
Area of Science:
- Protein folding dynamics
- Biomolecular structure and stability
Background:
- Prolyl cis/trans isomerization is a critical, often rate-limiting, step in protein folding.
- The N2 domain of gene-3-protein exhibits a native-state cis/trans equilibrium at Pro161.
Purpose of the Study:
- Investigate the interplay between protein folding and prolyl isomerization in the N2 domain.
- Identify the structural and energetic determinants of prolyl isomerization control.
Main Methods:
- Utilized mutational analysis and Φ-value analysis to probe the folding nucleus.
- Employed NMR spectroscopy to determine the structures of cis- and trans-Pro161 conformations.
Main Results:
- Identified a discrete folding nucleus around Pro161, which forms early and drives the cis/trans equilibrium.
- Found that variations distant from the Pro161-loop have minimal effect on the cis/trans ratio.
- Determined that cis-Pro161 conformation is more compact with enhanced hydrogen bonding, increasing stability by ~10 kJ·mol⁻¹.
Conclusions:
- Prolyl isomerization in the N2 domain is governed by a localized folding nucleus, not global stability.
- Localized energetic coupling integrates prolyl isomerization into the folding landscape, optimizing native structure and cis-conformation establishment.
Related Concept Videos
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
799
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...
799
01:25Protein Folding
7.7K
Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
7.7K
01:15¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
1.0K
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.
1.0K
01:10Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule
1.1K
In the AX proton spin system, proton A can sense the two spin states of a coupled proton X, resulting in a doublet NMR signal with two peaks of equal (1:1) intensity. When proton A is coupled to two equivalent protons (AX2 spin system), the spin states of each X can be aligned with or against the external field, creating three possible scenarios. This results in a 1:2:1 triplet signal, where the central peak corresponds to the chemical shift of A and is twice as large or intense as the...
1.1K
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
989
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
989
01:13Protein Organization
136.2K
Overview
136.2K