Stefan Krimmer Email & Phone Number

New York, Ny, Us

New York, Ny, Us

Department Of Pharmacology, Laboratory Of Dr. J. Schlessinger

Teaming up with a fellow postdoc, I used cryo-EM to determine the structures of wild-type and 2 oncogenic mutants of the full-length receptor tyrosine kinase KIT in complex with its ligand SCF. These cryo-EM structures reveal molecular-level insights into the activation mechanism of KIT and its oncogenic activation, unveiling a novel target for therapeutic intervention against KIT-driven cancers and diseases. Specifically, I have:● Collaborated closely with a cryo-EM expert lab to gain hands-on cryo-EM training. Introduced this technique to our lab, training colleagues in all aspects of cryo-EM.● Proficiently designed, cloned, expressed, and purified various constructs of full-length and truncated RTKs (KIT, ALK), cytokines (SCF, METRNL, AUG-α, AUG-β), and signaling pathway proteins (PLCγ-1, PI3Kα) from bacterial, insect, and mammalian cell expression systems.● Successfully reconstituted detergent-solubilized membrane protein complexes using various stabilizing agents, such as amphipols, and peptidiscs. Identified optimal conditions for preparing grids of soluble and membrane proteins for negative staining EM and cryo-EM.● Held “superuser” status operating electron microscopes (Tecnai T12, Glacios) for grid screening and data collection using SerialEM software. Processed data using cryoSPARC and RELION software and deposited 4 maps in the EMDB.● Generated stable cell lines expressing KIT mutants and assessed their signaling activity by Western blot, establishing a functional correlation with cryo-EM structural observations.● Published 1 co-first authored paper in PNAS, and 1 co-authored paper in Nature. Delivered an oral presentation of my research findings at the 9th New England Cryo-EM Symposium (>140 participants), receiving positive feedback from expert attendees.

Department Of Chemistry, Laboratory Of Dr. W. L. Jorgensen

Collaborating cross-functionally with synthetic and computational chemists, I worked on the structure-based design of small-molecule ligands selective for the pseudokinase (PK) domain of JAK2 kinase, a key initiator of intracellular signaling involved in cancers and other diseases. At the time, the PK domain was considered a potential innovative anti-cancer target. Furthermore, I collaborated on the structure-based design of MIF inhibitors. Our efforts led to nanomolar binders against both JAK2 PK and MIF. Specifically, I have:● Crafted a comprehensive research project proposal focused on the structure-based design of JAK2 PK ligands, securing a 2-year postdoctoral fellowship award from the German Research Foundation (DFG) totaling $109,000 in funds.● Performed protein expression and purification using bacterial, insect, and mammalian cell systems. Applied a range of purification techniques, ensuring high-quality protein for biophysical measurements and protein crystallization.● Optimized crystallization conditions and introduced a co-crystallization protocol. Independently collected X-ray data in-house and at the synchrotron and solved and interpreted 20+ crystal structures of protein–ligand complexes. The gained structural insights were essential for the rational design of potent binders.● Established and performed the Microscale thermophoresis (MST) assay to determine the affinities of small-molecule ligands binding to the truncated pseudokinase domain of JAK2. The assay provided robust binding data, facilitating the design of highly potent binders. ● Established and conducted an in vitro [γ-32P]ATP kinase assay to evaluate the enzymatic activity of full-length JAK2. This functional assay played a crucial role in testing the hypothesis that the kinase activity of JAK2 can be modulated by selective ATP displacement from the pseudokinase domain using small-molecule ligands.● Published 1 co-first authored paper and 6 co-authored papers.

Deptartment Of Pharmaceutical Chemistry, Laboratory Of Dr. G. Klebe

In close collaboration with a synthetic chemist, I investigated the impact of water molecules on protein-inhibitor binding through the analysis of kinetic, thermodynamic, and structural data of a congeneric series of small-molecule inhibitors binding to a metalloprotease. The obtained insights provide a rather general concept for how to rationally enhance ligand affinity. Furthermore, I engaged in a fragment-based screening campaign. Specifically, I have:● Independently characterized the structure-activity relationship of 20 small-molecule inhibitors using X-ray crystallography and isothermal titration calorimetry (ITC). ● Established and maintained a collaboration with GE Healthcare Life Sciences, focusing on measuring the binding kinetics of small-molecule inhibitors using surface plasmon resonance (SPR). ● Identified a poorly hydrated protein pocket by Xenon derivatization and MAD phasing, revealing its role in achieving an 41,000-fold affinity boost upon filling with an isobutyl group. This finding presents a promising drug design strategy.● Participated in a 13-member team that performed high-throughput screening of a 361-entry fragment library against an aspartic protease using crystallography. This approach led to the identification of 71 hits, 31 of which were undetected by other screening techniques, underscoring crystallography as a primary fragment screening technique in early stages of drug discovery.● Published 5 co-first authored and 7 co-authored papers.● Received the 2018 PhD Award in Medicinal/Pharmaceutical Chemistry from the German Chemical Society, recognized for an outstanding dissertation that made significant contributions to the field.● Presented my research at 6 national and international conferences, including the DiPIA conference in 2012 held in Beijing, China, for which I was awarded a scholarship from the German Academic Exchange Service (DAAD) to attend and present my work.

Supervised 500+ pharmacy students in practical laboratory courses focused on qualitative and quantitative drug analysis, demonstrating strong leadership, communication, and organizational skills. Conducted seminars, administered oral exams, and graded written exams, with a track record of successful student outcomes.

Department Of Pharmaceutics And Pharmaceutical Chemistry, Laboratory Of Dr. J. Kopeček

Conducted research for my Master’s thesis in pharmacy at the University of Utah, focusing on the synthesis and characterization of block copolymer micelles for drug delivery. This work contributed to the degree awarded by Martin Luther University of Halle-Wittenberg, Germany, and resulted in 1 first-author publication.

Phd, Pharmaceutical Chemistry, Summa Cum Laude (Highest Grade, In Top 12% Of Phd Graduates That Year)

Master'S Degree, Pharmacy

Pharmacy