2013 Young Investigator Award Nominee: Björn Meyer

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What drove you to choose a career in bioanalysis?

In High School in 1995, I had to write a term paper about modern methods for molecular structure determination. I was not very excited about this unwieldy topic. However, it was the first time that my interest was aroused for analytical chemistry. I went on to study pharmacy because I thought it could be the best way to combine my different scientific areas of interest: biology, medicine and analytical chemistry. At the end of the day, PhD and postdoctoral studies in mass spectrometry and proteomics made me want to stay in the field of bioanalysis.

Describe the main highlights of your bioanalytical research, and its importance to the bioanalytical community both now and in the future.

My PhD and postdoctoral research in Michael Karas’ laboratory at University of Frankfurt added some new methodical ideas to the field of proteomics. My focus has been and still is to develop MALDI-MS methods. One fundamental challenge in bioanalysis is the improvement of proteomic workflows for proteins, which are hardly accessible to trypsin proteolysis. As a start, I developed a gel-based MALDI-MS workflow for the analysis of protein complexes containing extremely hydrophobic subunits. Two studies using this technique provided new insights into the composition and functionality of the respiratory chain. Especially the use of less specific cutting enzymes such as chymotrypsin and elastase contributed to the required protein sequence coverage to answer the biological problem. The application of such enzymes was afterwards not only studied in detail for the gel- but also the LC-based MALDI-MS approach. I performed several follow-up studies to refine both MALDI-based strategies, i.e. I developed a new polyacrylamide gel system and many proteolysis protocols including separation and interpretation strategies for highly complex peptide mixtures. Until now, this research has resulted in 19 publications (three first-, five senior- and eleven co-authorships.

Describe the most difficult challenge you have encountered in the laboratory and how you overcame it?

A long term interest of the respiratory chain community was to identify structural components involved in the active/inactive enzyme transition of respiratory chain complex I. A clever fluorescence labeling strategy followed by doubled sodium dodecyl sulfate-polyacrylamide gel electrophoresis depicted surprisingly only one difference between the two enzyme states but the identification of this distinct gel spot failed with common proteomic methods. The use of specific cutting enzymes was unsuccessful. I knew from earlier work that proteins out of the diagonal in doubled sodium dodecyl sulfate-polyacrylamide gel electrophoresis are extremely hydrophobic. Therefore, the main idea was to apply harsher but still controllable cleavage conditions. I experimented with so-called unspecific enzymes, such as, chymotrypsin, elastase, pepsin and proteinase K. I had already figured out that some unspecific enzymes generate peptide patterns, which were not as random as the complete proteomic community thought at that time. The significant proof, however, was still missing and the verification took me an additional year. That is why I renamed some enzymes as less specific later on. The application of such less specific enzymes identified the integral membrane protein ND3, one of the most hydrophobic subunits of respiratory chain complex I as an essential structural component.

Where do you see your career in bioanalysis taking you?

I see myself as a future principal investigator at a university. My main research interest will still be the development of MALDI-MS techniques to advance the analysis of different biomolecules. My current position in Mannheim opens new exciting perspectives in this context. I supplement my expertise in protein analysis more and more by analytical methods for different lipid classes and small molecules (drugs and metabolites). Furthermore, pharmaceutical technology is applied in some projects. Together with the focus of the research center in Mannheim to develop methods in the relatively new fields of MS imaging and biotyping, I will have a good basis to generate new ideas for proteome, lipidome and metabolome analysis. Due to the change from pure academic to applied science, my future work will also be oriented towards fields of application in industry.

How do you envisage the field of bioanalysis evolving in the future?

The bioanalysis field will focus more on the qualitative and quantitative analysis of protein isoforms in the future, because only the identification and quantification of the right isoform ensures that the connection to the investigated function in a proteomic study is correct. Therefore, high or 100% sequence coverage is needed to detect preferably all post-translational modifications and splicing variants. A combined applicationof specific and less specific proteases will support to achieve this aim. The unambiguous peptide identification will be simplified by the permanent improvement in the mass spectrometric field, i.e. speed, sensitivity, mass accuracy and resolving power. The mass spectrometric developments, especially in the field of high resolution mass analyzers (e.g., Orbitrap and FT-ICR) will open the door to top-down proteomics for more bioanalysts. The main challenge will be the development of separation methods for intact proteins. The currently existing electrophoresis and chromatographic techniques are too limited in their resolving powers. Another ambition will be to correlate the results of protein species, lipidome and metabolome analysis because only the interaction of all biomolecules can define a biological process in a complete way. In this context, MALDI-Imaging techniques will be used to analyze the spatial distribution of abundant biomolecules.

Please list 5 of your recent publications, and select one that best highlights your career to date in the field of bioanalysis.

Meyer B, Wittig, I, Trifilieff E, Karas M, Schägger H. Identification of two proteins associated with mammalian ATP synthase. Mol Cell Proteomics 6, 1690–1699 (2007).

Rietschel B, Baeumlisberger D, Arrey TN et al. The benefit of combining nLC-MALDI-Orbitrap MS data with nLC-MALDI-TOF/TOF data for proteomic analyses employing elastase. J Proteome Res. 8(53), 17–24(2009).

Papasotiriou DG, Jaskolla TW, Markoutsa S, Baeumlisberger D, Karas M, Meyer B. Peptide mass fingerprinting after less specific in-gel proteolysis using MALDI-LTQ-Orbitrap and 4-chloro-alpha-cyanocinnamic acid. J Proteome Res. 9, 2619–2629. (2010).

Arrey TN, Rietschel B, Papasotiriou DG et al. Approaching the complexity of elastase-digested membrane proteomes using off-gel IEF/nLC-MALDI-MS/MS. Anal Chem. 82(2), 145–149 (2010).

Gao Y, Meyer B, Sokolova L et al. Heme-copper terminal oxidase using both cytochrome c and ubiquinol as electron donors. Proc Natl Acad Sci USA. 109, 3275–3280 (2012).

First choice: Gao Y, Meyer B, Sokolova L et al. Heme-copper terminal oxidase using both cytochrome c and ubiquinol as electron donors. Proc Natl Acad Sci USA. 109, 3275–3280 (2012).

Reasoning: The publication with Nobel Laureate Hartmut Michel might perhaps best highlight my contribution to the bioanalysis field. Indeed, it is only a second authorship but it demonstrates the relevance of my former work, i.e., the development of a gel-based MALDI method for hydrophobic proteins and the application of less specific enzymes in gel- and LC-based proteomics.