title: Hexameric supramolecular scaffold orients carbohydrates to sense bacteria.
abstract: Carbohydrates are integral to biological signaling networks and cell-cell interactions, yet the detection of discrete carbohydrate-lectin interactions remains difficult since binding is generally weak. A strategy to overcome this problem is to create multivalent sensors, where the avidity rather than the affinity of the interaction is important. Here we describe the development of a series of multivalent sensors that self-assemble via hydrophobic supramolecular interactions. The multivalent sensors are comprised of a fluorescent ruthenium(II) core surrounded by a heptamannosylated β-cyclodextrin scaffold. Two additional series of complexes were synthesized as proof-of-principle for supramolecular self-assembly, the fluorescent core alone and the core plus β-cyclodextrin. Spectroscopic analyses confirmed that the three mannosylated sensors displayed 14, 28, and 42 sugar units, respectively. Each complex adopted original and unique spatial arrangements. The sensors were used to investigate the influence of carbohydrate spatial arrangement and clustering on the mechanistic and qualitative properties of lectin binding. Simple visualization of binding between a fluorescent, multivalent mannose complex and the Escherichia coli strain ORN178 that possesses mannose-specific receptor sites illustrates the potential for these complexes as biosensors.
authors.affiliation: Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
authors.forename: Dan
authors.initials: D
authors.lastname: Grünstein
authors.forename: Maha
authors.initials: M
authors.lastname: Maglinao
authors.forename: Raghavendra
authors.initials: R
authors.lastname: Kikkeri
authors.forename: Mayeul
authors.initials: M
authors.lastname: Collot
authors.forename: Konstantin
authors.initials: K
authors.lastname: Barylyuk
authors.forename: Bernd
authors.initials: B
authors.lastname: Lepenies
authors.forename: Faustin
authors.initials: F
authors.lastname: Kamena
authors.forename: Renato
authors.initials: R
authors.lastname: Zenobi
authors.forename: Peter H
authors.initials: PH
authors.lastname: Seeberger
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002241:Carbohydrates / Q000737:chemistry*; D004926:Escherichia coli / Q000302:isolation & purification*; D005456:Fluorescent Dyes / Q000737:chemistry*; D008358:Mannose / Q000737:chemistry; D018613:Microscopy, Confocal; D009942:Organometallic Compounds / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry; D047392:beta-Cyclodextrins / Q000737:chemistry
chemical_list: D002241:Carbohydrates; D005456:Fluorescent Dyes; D009942:Organometallic Compounds; D047392:beta-Cyclodextrins; D012428:Ruthenium; C031215:betadex; D008358:Mannose