Professor Kristina 'Kicki' Håkansson

Professor Kristina 'Kicki' Håkansson
Department of Chemistry
Director, Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory,
Florida State University

Tyrosine Sulfation: a Tricky Post-translational Modification Requiring High End Mass Spectrometry

Tyrosine sulfation, an understudied but crucial posttranslational modification cannot be directly detected in conventional nanoflow liquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) due to the extreme sulfate lability. The complete lack of sulfate retention upon collisional activation also presents a challenge for conventional proteomics software. We report detection of sulfate- retaining fragments from LC-electron capture dissociation (ECD) and nanoLC-electron transfer-higher energy collision dissociation (EThcD), allowing for identification of novel sulfation sites. MSFragger open search identifies sulfopeptide candidates based on MS1 accurate mass shift; however, isobaric interferences present a challenge, including alkylation artifacts combined with sequence variants and sodium adduction. The aforementioned challenges were culprits in recent misidentification of tyrosine sulfation in histone H3. The latter results were surprising as the tyrosylprotein sulfotransferases (TPST1 and TPST2) are only known to exist in the Golgi. Thus, cytosolic and nuclear proteins are not expected to be sulfated. Reannotation of the associated tandem mass spectra and additional experiments that found a lack of evidence to support H3Y99 sulfation will be presented. Furthermore, recent top- down proteomics strategies, showing benefits for tyrosine sulfation characterization will be shown.

Kristina 'Kicki' Håkansson

Dr. Kristina (Kicki) Håkansson received M.Sc. and Ph.D. degrees in Molecular Biotechnology from Uppsala University, Sweden. She was a Swedish Foundation for International Cooperation in Research and Higher Education (STINT) postdoctoral fellow with Prof. Alan G. Marshall at the National High Magnetic Field Laboratory, Florida State University. In 2003, she joined the faculty in Chemistry at the University of Michigan. Dr. Håkansson received a Searle Scholar Award (2004), an American Society for Mass Spectrometry Research Award (2005), an Eli Lilly Analytical Chemistry Award (2005), and an NSF Career Award (2006). In 2009, she was promoted to Associate Professor, with tenure and, in 2013, to Professor. In 2016 she received the Biemann Medal from the American Society for Mass Spectrometry, in 2018 an Agilent Thought Leader award, and in 2020 the Berzelius Gold Medal from the Swedish Mass Spectrometry Society. In 2024, she moved to Florida State University as Director of the Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory and Professor of Chemistry & Biochemistry. Her research interests are in Analytical Chemistry and Chemical Biology with a focus on biomolecular mass spectrometry, including gas-phase activation methods, posttranslational modifications, carbohydrate structural determination, and functional studies of natural product biosynthetic enzymes.

Host: Professor Rene Boiteau