title: Switchable cucurbituril-bipyridine beacons.
abstract: 4-Aminobipyridine derivatives form strong inclusion complexes with cucurbit[6]uril, exhibiting remarkably large enhancements in fluorescence intensity and quantum yields. The remarkable complexation-induced pK(a) shift (DeltapK(a)=3.3) highlights the strong charge-dipole interaction upon binding. The reversible binding phenomenon can be used for the design of switchable beacons that can be incorporated into cascades of binding networks. This concept is demonstrated herein by three different applications: 1) a switchable fluorescent beacon for chemical sensing of transition metals and other ligands; 2) direct measurement of binding constants between cucurbit[6]uril and various nonfluorescent guest molecules; and 3) quantitative monitoring of biocatalytic reactions and determination of their kinetic parameters. The latter application is illustrated by the hydrolysis of an amide catalyzed by penicillin G acylase and by the elimination reaction of a beta-cabamoyloxy ketone catalyzed by aldolase antibody 38C2.
authors.affiliation: Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel.
authors.forename: Mantosh K
authors.initials: MK
authors.lastname: Sinha
authors.forename: Ofer
authors.initials: O
authors.lastname: Reany
authors.forename: Galit
authors.initials: G
authors.lastname: Parvari
authors.forename: Ananta
authors.initials: A
authors.lastname: Karmakar
authors.forename: Ehud
authors.initials: E
authors.lastname: Keinan
mesh_terms: D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000737:chemistry*; D005453:Fluorescence; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism; D007140:Immunoglobulin Fab Fragments / Q000378:metabolism; D047028:Macrocyclic Compounds / Q000737:chemistry*; D015394:Molecular Structure; D010399:Penicillin Amidase / Q000378:metabolism*; D000099246:Cucurbit(n)urils
chemical_list: D015082:2,2'-Dipyridyl; D005634:Fructose-Bisphosphate Aldolase; D007140:Immunoglobulin Fab Fragments; D047028:Macrocyclic Compounds; D010399:Penicillin Amidase; D000099246:Cucurbit(n)urils; C109536:antibody aldolase