Application of High-Sensitivity UV photoemission Spectroscopy to Examine the Electronic Structure of Thermophilic Rhodopsin

Abstract

The electronic structures of materials such as HOMO and LUMO are essential information to understand their functions. Photoemission spectroscopy, which is the most standard technique to examine the electronic structures of various materials, has been not well applied to biomolecules mostly due to sample charging and poor sensitivity. Very recently, we have developed high-sensitivity photoemission spectroscopy (HS-PES) using low photon energy. In this study, HS-PES has been successfully applied to a thermophilic rhodopsin (TR) film. The high sensitivity of our technique enabled to observe the HOMO region of retinal part in TR without any problem due to sample charging. This technique is expected to explore the electronic structures of various proteins.

Keywords:

• High-Sensitivity Photoemission Spectroscopy
• Protein
• Thermophilic Rhodopsin
• Ionization Energy
• Electronic Structure

Acknowledgements

This research was supported by JSPS through the “Funding Program for World-leading Innovative R&D on Science and Technology (FIRST Program)” initiated by the Council for Science and Technology Policy and KAKENHI Grant Numbers 25288114 and 16H04222, and the collaboration project of Molecular Chirality Research Center.