Shedding Light on Luminescence - Scientists at HZB reveal the structure of a designer protein
Band model of the fluorescent protein “Dreiklang”,
the structure of which was measured at the electron
storage ring BESSY.
Fluorescent proteins are important investigative tools in the biosciences: Coupled to other proteins, they help us to study the processes of life inside cells and organisms at the molecular level. Fluorescent proteins are made to light up at specific target sites or to become dark again where necessary. In other words, they are switched on and off like light bulbs. Now, for the first time, at Helmholtz-Zentrum Berlin (HZB) scientists have studied the structural characteristics involved in fluorescence on one single protein crystal when switched on and when switched off. Their results are published in Nature Biotechnology (doi:10.1038/nbt.1952).
The researchers from the Max Planck Institute for Biophysical Chemistry in Göttingen and from Freie Universität Berlin performed their work on the MX Beamline BL14.2 at HZB’s electron storage ring BESSY, which is co-operated together with FU-Berlin, HU, MDC and FMP as part of the Joint Berlin MX Laboratory. The intense X-ray light on the beamline can be used to measure protein crystals at extremely high resolution. The object of study was a green-fluorescent protein dubbed “Dreiklang”. They first switched the protein crystal from fluorescent to non-fluorescent state at room temperature – they “switched it off”. Next, the scientists measured the deep-frozen crystal at around minus 170 degrees Celsius on the BESSY beamline.
“Normally a protein crystal breaks when heated back up to room temperature after measurement,” Dr. Uwe Müller, head of the HZB “Macromolecular Crystallography” workgroup, describes the special nature of the study: “In this case, however, it was possible to keep the protein functional.” The researchers brought the protein crystal back into fluorescent state at 30 degrees Celsius, then froze it and studied it a second time on the beamline. The subsequent data analysis revealed that the protein’s structure differs when switched on or switched off by the number of water molecules embedded in it.
“The study of the Dreiklang molecule broke new ground at BESSY,” Uwe Müller says. It is a designer protein that does not naturally exist in this form. Müller continues: “The MX beamline lets scientists study not only natural proteins but even entirely novel materials. The work with Dreiklang has taken us another step forward in HZB’s core research area of ‘Functional Materials’,” Müller concludes.
- The future of corals – what X-rays can tell usThis summer, it was all over the media. Driven by the climate crisis, the oceans have now also passed a critical point, the absorption of CO2 is making the oceans increasingly acidic. The shells of certain sea snails are already showing the first signs of damage. But also the skeleton structures of coral reefs are deteriorating in more acidic conditions. This is especially concerning given that corals are already suffering from marine heatwaves and pollution, which are leading to bleaching and finally to the death of entire reefs worldwide. But how exactly does ocean acidification affect reef structures?
Prof. Dr. Tali Mass, a marine biologist from the University of Haifa, Israel, is an expert on stony corals. Together with Prof. Dr. Paul Zaslansky, X-ray imaging expert from Charité Berlin, she investigated at BESSY II the skeleton formation in baby corals, raised under different pH conditions. Antonia Rötger spoke online with the two experts about the results of their recent study and the future of coral reefs.
- Energy of charge carrier pairs in cuprate compoundsHigh-temperature superconductivity is still not fully understood. Now, an international research team at BESSY II has measured the energy of charge carrier pairs in undoped La₂CuO₄. Their findings revealed that the interaction energies within the potentially superconducting copper oxide layers are significantly lower than those in the insulating lanthanum oxide layers. These results contribute to a better understanding of high-temperature superconductivity and could also be relevant for research into other functional materials.
- Electrocatalysis with dual functionality – an overviewHybrid electrocatalysts can produce green hydrogen, for example, and valuable organic compounds simultaneously. This promises economically viable applications. However, the complex catalytic reactions involved in producing organic compounds are not yet fully understood. Modern X-ray methods at synchrotron sources such as BESSY II, enable catalyst materials and the reactions occurring on their surfaces to be analysed in real time, in situ and under real operating conditions. This provides insights that can be used for targeted optimisation. A team has now published an overview of the current state of knowledge in Nature Reviews Chemistry.