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4:00 pm
Room 304, Chemistry Building

Hip to be square: Building brighter fluorophores with azetidine


Dr. Luke Lavis
Janelia Farm Research Campus at Howard Hughes Medical Institute

Hosted by: Professor Andreas Gahlmann

Specific labeling of biomolecules with bright, photostable fluorophores is the keystone of fluorescence microscopy. An expanding method to label cellular components utilizes genetically encoded self-labeling tags, which enable the attachment of chemical fluorophores to specific proteins inside living cells. This strategy combines the genetic specificity of fluorescent proteins with the favorable photophysics of synthetic dyes. However, intracellular labeling using these techniques requires small, cell-permeable fluorophores, thereby limiting utility to a small number of classic, unoptimized dyes. We describe a simple structural modification to standard fluorophores that improves brightness and photostability while preserving other spectral properties and cell permeability. Inspired by computational experiments, we replaced the N,N-dimethylamino substituents in tetramethylrhodamine with a four-membered azetidine ring. This net addition of two carbon atoms doubles the quantum efficiency and improves the photon yield in living cells. The novel substitution is generalizable to fluorophores from different structural classes, yielding a palette of synthetically tractable chemical dyes with improved quantum efficiency and enabling multicolor single-molecule experiments. These brighter versions of classic fluorophores can be further modified to fine-tune spectral and chemical properties for advanced imaging.





Luke D. Lavis was born in rural southern Oregon. He received his B.S. in Chemistry at Oregon State University in 2000, where he performed undergraduate research in synthetic organic chemistry with James D. White. Dr. Lavis then spent four years in industrial R&D at Molecular Probes in Eugene, OR and Molecular Devices in Sunnyvale, CA. Luke then entered graduate school at the University of Wisconsin–Madison and worked with Ronald T. Raines to develop strategies to trace the path of anticancer proteins in living cells. He received his Ph.D. in Organic Chemistry in 2008. Luke started his independent career at the Howard Hughes Medical Institute’s Janelia Research Campus as a Group Leader, also in 2008. At Janelia, Dr. Lavis works at the interface of chemistry and biology, developing labels for single-molecule imaging, dyes for super-resolution microscopy, and strategies for cell-type specific pharmacology.