Hedersdoktorsföreläsning med Vittal K. Yachandra

Dr. Vittal K. Yachandra arbetar på Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.

Motiveringen till hedersdoktorsutnämningen lyder:

Dr. Vittal K. Yachandra är biofysikalisk kemist och spektroskopist och har gjort enastående insatser för att utveckla röntgenspektroskopi vid synkrotroner och femtosekundskristallografi och röntgenspektroskopi vid XFEL-lasrar (X-ray free electron lasers).

Dr. Yachandras arbete har flyttat fram gränserna både för vår förståelse av fotosystem II och för kapaciteten hos storskaliga anläggningar. Hans prestationer kommer att få långvariga effekter i de kemiska, fysikaliska och biologiska samhällen som arbetar med synkrotroner och XFEL, och är mycket viktiga för utvecklingen av bioinspirerade, skalbara katalysatorer, tillverkade av grundämnen som finns i överflöd på jorden, vilket är absolut nödvändigt för övergången till ett fossilfritt samhälle.

Titel: 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."

Mer information

Dr. Yachandra kommer ta emot sitt hederstecken under vinterpromotionen den 31 januari. Mer om samtliga hedersdoktorer och vinterpromotionen hittar du här: https://www.uu.se/medarbetare/aktuellt-for-alla/arkiv/2025-01-14-nya-hedersdoktorer-vid-universitetet