Spin states of hemoprotein in physiological conditions probed by nitrogen K-edge X-ray absorption spectroscopy

A joint research team, including Shota Tsuru, Postdoctoral Researcher at the Computational Molecular Science Research Team, RIKEN Center for Computational Science (R-CCS), has successfully observed the spin states of the heme in myoglobin in aqueous solution at room temperature utilizing soft X-ray absorption spectroscopy at the nitrogen K-edge of the porphyrin ring in conjunction with electronic structure calculations.

The research team managed to observe peaks associated with the C=N π* orbitals of the porphyrin ring separately from nitrogen atoms abundantly present in the polypeptide chain. The analysis showed that the spin state of heme proteins, such as myoglobin, is influenced by temperature and the polypeptide chain, indicating the significance of in situ measurements in the functional state.

This research result was published online in the international academic journal Physical Chemistry Chemical Physics (PCCP) on August 24, 2026.
DOI : 10.1039/D6CP00764C

For more details, please see the following link: