title: A genetically encoded spin label for electron paramagnetic resonance distance measurements.
abstract: We report the genetic encoding of a noncanonical, spin-labeled amino acid in Escherichia coli. This enables the intracellular biosynthesis of spin-labeled proteins and obviates the need for any chemical labeling step usually required for protein electron paramagnetic resonance (EPR) studies. The amino acid can be introduced at multiple, user-defined sites of a protein and is stable in E. coli even for prolonged expression times. It can report intramolecular distance distributions in proteins by double-electron electron resonance measurements. Moreover, the signal of spin-labeled protein can be selectively detected in cells. This provides elegant new perspectives for in-cell EPR studies of endogenous proteins.
authors.affiliation: Department of Chemistry, Zukunftskolleg, and Konstanz Research School Chemical Biology, University of Konstanz , Universitätsstraße 10, 78457 Konstanz, Germany.
authors.forename: Moritz J
authors.initials: MJ
authors.lastname: Schmidt
authors.forename: Julia
authors.initials: J
authors.lastname: Borbas
authors.forename: Malte
authors.initials: M
authors.lastname: Drescher
authors.forename: Daniel
authors.initials: D
authors.lastname: Summerer
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000235:genetics; D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000235:genetics; D008958:Models, Molecular; D015394:Molecular Structure; D009865:Oocytes / Q000737:chemistry / Q000166:cytology / Q000378:metabolism; D013113:Spin Labels; D014981:Xenopus
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D013113:Spin Labels