Related Experiment Video
Updated: Mar 31, 2026

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
Study of the phase transition in lysozyme crystals by Raman spectroscopy
Anna V Frontzek1, Laurent Paccou2, Yannick Guinet2
1Jülich Center for Neutron Science (JCNS), Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, 85747 Garching, Germany; A.F. Ioffe Physical Technical Institute, Politekhnicheskaya ul. 26, 194021 St. Petersburg, Russian Federation.
Background:
Recently, it has been revealed that tetragonal lysozyme crystals show a phase transition at 307 K upon heating. The underlying mechanisms of the phase transition are still not fully understood. Here we focus on the study of high-frequency vibrational modes arising from the protein and their temperature evolution in the vicinity of Tph as well as on the detailed study of crystalline water dynamics near Tph.
Methods:
Raman experiments have been performed at temperatures 295–323 K including Tph. The low-frequency modes and the modes of fingerprint region, CH- and OH-stretching regions have been analyzed.
Results And Conclusions:
In spite of the absence of noticeable rearrangements in protein structure, the high-frequency vibrational modes of lysozyme located in the fingerprint region have been found to exhibit the features of critical dynamics near Tph. Pronounced changes in the dynamics of α-helixes and Tyr residues exposed on the protein surface point to the important role of H-bond rearrangements at the phase transition. Additionally the study of temperature evolution of OH-stretching modes has shown an increase in distortions of tertahedral H-bond network of crystalline water above Tph. These changes in water dynamics could play a crucial role in the mechanisms of the phase transition.
General Significance:
The present results shed light on the mechanisms of the phase transition in lysozyme crystals.
Related Concept Videos
Raman Spectroscopy: Overview
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
Raman Spectroscopy Instrumentation: Overview
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
UV–Vis Spectroscopy: Molecular Electronic Transitions
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
According to Hooke's law, the vibrational frequency is directly proportional to...
Phase Transitions: Melting and Freezing
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...

