title: Using Protein-Confined Proximity To Determine Chemical Reactivity.
abstract: Chemical reactivity is essential for functional modification of biomolecules with small molecules and the development of covalent drugs. The reactivity between a chemical functional group of a small molecule and that of a large biomolecule cannot be reliably predicted from the reactivity of the corresponding functional groups separately installed on two small molecules, because the proximity effect on reactivity resulting from the binding of the small molecule to the biomolecule is challenging to achieve by mixing two small molecules. Here we present a new strategy to determine the chemical reactivity of two functional groups in the context of close proximity afforded by proteins. The functional groups to be tested were separately installed at the interface of two interacting proteins in the format of amino acid side chains via the expansion of the genetic code. Reaction of the two functional groups resulted in covalent cross-linking of interacting proteins, readily detectable by gel electrophoresis. Using this strategy, we evolved new synthetases to genetically encode Nε-fluoroacetyllysine (FAcK), an isosteric fluorine analogue of acetyllysine. We demonstrated that fluoroacetamide installed on FAcK, previously thought inert to biological functional groups, actually reacted with the thiol group of cysteine when in proximity. This strategy should be valuable for accurately evaluating chemical reactivity of small molecules toward large biomolecules, which will help avoid undesired side reactions of drugs and expand the repertoire of functional groups to covalently target biomolecules.
authors: Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California, San Francisco , 555 Mission Bay Boulevard South, San Francisco, California 94158, United States.
authors: Tomonori
authors: T
authors: Kobayashi
authors: Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California, San Francisco , 555 Mission Bay Boulevard South, San Francisco, California 94158, United States.
authors: Christian
authors: C
authors: Hoppmann
authors: Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California, San Francisco , 555 Mission Bay Boulevard South, San Francisco, California 94158, United States.
authors: Bing
authors: B
authors: Yang
authors: Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California, San Francisco , 555 Mission Bay Boulevard South, San Francisco, California 94158, United States.
authors: Lei
authors: L
authors: Wang
mesh_terms: D000107:Acetylation; D000596:Amino Acids / Q000737:chemistry; D008025:Ligases / Q000737:chemistry* / Q000378:metabolism; D008239:Lysine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017020:Methanosarcina / Q000737:chemistry; D008968:Molecular Conformation
chemical_list: D000596:Amino Acids; D008025:Ligases; D008239:Lysine