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News

New scientific highlight- by MUST PI Richardson
FELs of Europe prize for Jeremy Rouxel- “Development or innovative use of advanced instrumentation in the field of FELs”
Ruth Signorell wins Doron prizefor pioneering contributions to the field of fundamental aerosol science
New FAST-Fellow Uwe Thumm at ETH- lectures on Topics in Femto- and Attosecond Science
International Day of Women and Girls in Science- SSPh asked female scientists about their experiences
New scientific highlight- by MUST PIs Milne, Standfuss and Schertler
EU XFEL Young Scientist Award for Camila Bacellar,beamline scientist and group leader of the Alvra endstation at SwissFEL
Prizes for Giulia Mancini and Rebeca Gomez CastilloICO/IUPAP Young Scientist Prize in Optics & Ernst Haber 2021
Nobel Prize in Chemistry awarded to RESOLV Member Benjamin List- for the development of asymmetric organocatalysis
NCCR MUST at Scientifica 2021- Lightning, organic solar cells, and virtual molecules
#NCCRWomen- NCCR MUST celebrates 50 years women’s right to vote in Switzerland
Kick-Off dynaMENT Mentoring for Women in Natural Sciences- with Ursula Keller as plenary speaker
Four new scientific highlights- by MUST PIs Chergui / Milne / Beaud / Staub, by Wolf / Röthlisberger, by Wörner, and Keller

Majed Chergui and co-workers: An ultraviolet analogue of 2D NMR

February 15, 2013

Unravelling electron and energy transfer processes of amino-acid residues in bio-systems

The past twenty years have witnessed a significant effort aimed at pushing the methods of multidimensional NMR spectroscopies from the radiofrequency domain into the optical domain, first in the infrared (vibrational multidimensional spectroscopy) and around the mid-2000’s in the visible range (electronic multidimensional spectroscopy), with the advantage of probing couplings between vibrational or electronic dipoles (chromophores) in biological systems that are orders of magnitude stronger than in NMR, while achieving a much higher time resolution of sub-picoseconds.
Pushing 2D spectroscopy further into the UV below 300 nm brings the additional advantage of accessing the absorption region of amino acid residues and nucleic acids. However, because of their large (30-50 nm) absorption band widths, 2D UV spectroscopy has remained a challenge. Recently, the group of Prof. Chergui has implemented the first experimental set-up for 2D UV spectroscopy and in a recent article in Science, they demonstrated its capabilities in the case of heme proteins. Indeed, in addition to disentangling the broad overlapping spectral contributions of three chromophores (the heme and the two tryptophan residues), they identified electron-transfer processes between one of the tryptophans and the heme. So far, it was always assumed that the tryptophan fluorescence is quenched by an energy transfer (so-called FRET) to the heme. These results question the systematic use of FRET to interpret the decay of the Trp fluorescence in biological systems, and therefore its general role as a “spectroscopic ruler”. On a broader perspective, the ability of 2D UV spectroscopy to detect couplings between chromophores in biosystems, offers a new tool to study protein-target interactions.

Mb-Etrans


 
  1. G. Auböck, C. Consani, F. van Mourik and M. Chergui (2012) Ultrabroadband femtosecond two-dimensional ultraviolet transient absorption. Opt. Lett., 37, 2337 (2012)
  2. C. Consani, G. Auböck, F. van Mourik and M. Chergui (2013) Ultrafast tryptophan-to-haem electron transfer in myoglobins: a two-dimensional UV spectroscopy study. Science (DOI: 10.1126/science.1230758).
     
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