Honorary doctorate lecture with Vittal K. Yachandra

Dr. Vittal K. Yachandra works at the Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.

The motivation for the honorary doctorate states:

Dr. Vittal K. Yachandra is a biophysical chemist and spectroscopist who has made outstanding contributions to the development of X-ray spectroscopy at synchrotrons and to serial femtosecond crystallography and X-ray spectroscopy at X-ray free electron lasers (XFELs).

Dr. Yachandra’s work has pushed the boundaries of both our understanding of photosystem II and of the capabilities of large-scale facilities. His achievements will have long-lasting effects in the chemical, physical and biological communities working with synchrotrons and XFELs, and are highly important for the development of bio-inspired, scalable catalysts, made of earth-abundant elements, urgently required for the transition to a fossil-free society.

Title: Capturing Reaction Dynamics and Catalytic Intermediates in Photosynthetic Systems and Metalloenzymes Using X-ray Free Electron Lasers

Abstract: "The development of XFELs has opened up opportunities for studying the dynamics of biological systems beyond what is possible at synchrotron radiation sources. Intense, ultrashort X-ray pulses from the XFELs enable us to collect X-ray diffraction from protein crystals and/or apply hard and soft X-ray spectroscopy techniques to study transition metal containing catalytic sites in dilute systems or protein crystals. By taking advantage of the ultra-bright, femtosecond X-ray pulses, one can collect the diffraction or spectroscopy data under functional conditions of temperature and pressure, in a time-resolved manner, after initiating reactions with light or substrates, and follow the chemical dynamics during catalytic reactions and electron transfer. Such an approach is particularly beneficial for biological materials and aqueous solution samples that are susceptible to X-ray radiation damage. We have developed spectroscopy and diffraction techniques necessary to utilize the capability of the XFEL X-rays for a wide-variety of systems, such as Photosystem I and II and other metalloenzymes of relevance to health or renewable energy, and to study their chemistry under functional conditions of temperature and pressure. One such method that we have developed is the simultaneous collection of X-ray crystallography and X-ray spectroscopy data, to look at the overall geometric structural changes of proteins and the electronic structure changes at metal catalytic sites to capture the dynamics and the reaction intermediates during the catalytic reaction. We have used the above method to study the water oxidation reaction of Photosystem II, a multi-subunit protein complex, in which the Mn4CaO5 cluster catalyzes the reaction, the dynamics of charge transfer in photosynthetic reaction centers, and the catalytic reactions at the Fe, Mn or Ni active sites of metalloenzymes such as methane monooxygenase, hydrogenases, ribonucleotide reductase and other systems. The current status of this research and the future direction and development of related X-ray techniques at XFELs will be presented."

More information

Dr. Yachandra will receive his token of honour at the Winter Conferment Ceremony on January 31. More information about this year’s recipients of honorary doctorates and the Winter Conferment Ceremony can be found here: https://www.uu.se/en/staff/news/archive/2025-01-14-new-honorary-doctors-at-the-university