Related Experiment Video
Updated: May 12, 2026

Advances in Nanoscale Infrared Spectroscopy to Explore Multiphase Polymeric Systems
Published on: June 23, 2023
Simulated pH-difference infrared spectra: Application to the PsbS monomer
Kim E van Adrichem1, Nicoletta Liguori2, Roberta Croce2
1Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands.
Abstract:
In strong sunlight, plants prevent photo-oxidation by dissipating excess energy absorbed. PsbS, a membrane protein that responds to light-induced pH changes in the thylakoid lumen, initiates this energy quenching. Recent molecular dynamics simulations predicted the structures and protonation states of the monomeric PsbS at different pH values. In this paper, we present a simulation protocol for predicting the pH-difference spectra starting from molecular dynamics simulations. We use it to simulate the infrared spectroscopy of the low- and neutral-pH structures of the PsbS monomers previously predicted and analyze the origin of the spectral changes. Comparison with the experimental spectra of PsbS suggests that dimer formation may change the structure and spectroscopy significantly. Analysis of the simulated infrared difference spectra demonstrates that the response to the pH change in the monomer is rather global and the largest change arises from the transmembrane helices.
More Related Videos
Related Concept Videos
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
IR Spectroscopy: Molecular Vibration Overview
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...
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
According to Hooke's law, the vibrational frequency is directly proportional to the...
IR Spectrum Peak Intensity: Dipole Moment
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.

