title: A synthetic host-guest system achieves avidin-biotin affinity by overcoming enthalpy-entropy compensation.
abstract: The molecular host cucurbit[7]uril forms an extremely stable inclusion complex with the dicationic ferrocene derivative bis(trimethylammoniomethyl)ferrocene in aqueous solution. The equilibrium association constant for this host-guest pair is 3 x 10(15) M(-1) (K(d) = 3 x 10(-16) M), equivalent to that exhibited by the avidin-biotin pair. Although purely synthetic systems with larger association constants have been reported, the present one is unique because it does not rely on polyvalency. Instead, it achieves its extreme affinity by overcoming the compensatory enthalpy-entropy relationship usually observed in supramolecular complexes. Its disproportionately low entropic cost is traced to extensive host desolvation and to the rigidity of both the host and the guest.
authors: ICORP Entropy Control Project (JST) and Department of Applied Chemistry, Osaka University, Yamada-oka, Suita 565-0871, Japan.
authors: Mikhail V
authors: MV
authors: Rekharsky
authors: Tadashi
authors: T
authors: Mori
authors: Cheng
authors: C
authors: Yang
authors: Young Ho
authors: YH
authors: Ko
authors: N
authors: N
authors: Selvapalam
authors: Hyunuk
authors: H
authors: Kim
authors: David
authors: D
authors: Sobransingh
authors: Angel E
authors: AE
authors: Kaifer
authors: Simin
authors: S
authors: Liu
authors: Lyle
authors: L
authors: Isaacs
authors: Wei
authors: W
authors: Chen
authors: Sarvin
authors: S
authors: Moghaddam
authors: Michael K
authors: MK
authors: Gilson
authors: Kimoon
authors: K
authors: Kim
authors: Yoshihisa
authors: Y
authors: Inoue
mesh_terms: D001360:Avidin / Q000737:chemistry*; D001710:Biotin / Q000737:chemistry*; D019921:Biotinylation; D001952:Bridged-Ring Compounds / Q000737:chemistry*; D002151:Calorimetry / Q000379:methods; D002621:Chemistry / Q000379:methods*; D018360:Crystallography, X-Ray / Q000379:methods; D019277:Entropy; D006860:Hydrogen Bonding; D007093:Imidazoles / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D019809:Streptavidin; D013816:Thermodynamics; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
chemical_list: D001360:Avidin; D001710:Biotin; D001952:Bridged-Ring Compounds; D007093:Imidazoles; D019809:Streptavidin; C456276:cucurbit(7)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils