2014 July

Probing Protein Structure with Ultraviolet Photodissociation

Monday, 28th July 2014Miscellaneous

In top-down proteomics studies proteins are characterized by iterative fragmentation and analysis via mass spectrometry. Different fragmentation techniques have their own strengths and weaknesses, and ultraviolet photodissociation (UVPD) offers the benefit of relatively consistent fragmentation along the protein backbone. In our most recent publication, we show that the technique also can distinguish subtle differences in the protein structure .

We used ion-mobility mass-spectrometry to resolve two distinct conformations of the 11+ charge state of the protein ubiquitin. UVPD fragmentation of those conformers, which are identical in their chemical composition and charge, reveals significantly different fragmentation patterns, which arise mostly from cleavage around a single residue, proline-19. Using both spectral data and molecular dynamics simulations, we could attribute these fragmentation differences, to cis–trans isomerization of the peptide bond N-terminal to that residue.

Our data provides first evidence for UVPD being sensitive to the higher order structure of proteins. Furthermore, conformer-selective UVPD can potentially serve as tool for the structural analysis of proteins in the gas phase.

Photodissociation of Conformer-Selected Ubiquitin Ions Reveals Site-Specific Cis/Trans Isomerization of Proline Peptide Bonds
Stephan Warnke, Carsten Baldauf, Michael T. Bowers, Kevin Pagel, and Gert von Helden
dx.doi.org/10.1021/ja502994b | J. Am. Chem. Soc. 2014, 136, 10308−10314

Link to paper: http://pubs.acs.org/doi/pdf/10.1021/ja502994b
Link to Spotlight: http://pubs.acs.org/doi/pdf/10.1021/ja507050z

International Symposium on Inorganic Insights into Catalysis

Monday, 14th July 2014Miscellaneous

On the occasion of Robert Schlögl’s 60th birthday, an international symposium was held in Berlin on July 3-4, 2014. Its theme were Inorganic Insights into Catalysis.

Session chairs and speakers comprised outstanding scientists in the field of heterogeneous catalysis, including former and current co-workers of Robert Schlög’s at the Fritz Haber Institute.

A highlight of the symposium were the after dinner talks by Ferdi Schüth (Max Planck Institut für Kohlenforschung) on ‘The “Energiewende” and obstacles in its practical implementation’ and by Eberhard Umbach (Würzburg University) on ‘Energy storage – The Crux of the “Energiewende”?’. (Link to the webpage of the symposium)

These were two exciting days filled with state-of-the-art science and inspiring personal encounters.