title: Assessment of Cooperativity in Ternary Peptide-Cucurbit[8]uril Complexes.
abstract: Evaluating cooperativity for cucurbit[8]uril (CB[8])-mediated ternary complexation is required for understanding and advancing designs of such ternary self-assembled systems. A key issue is to dissect the contributions of the binding steps of the first and second guest molecules to the overall ternary complex formation energy. This is addressed by performing concentration-dependent titrations between CB[8] and guests by means of concentration-dependent calorimetric and1H-NMR titrations. The sensitivity of the fitting of the cumulative heat of complexation of the calorimetric titrations is evaluated in terms of fitting error and enthalpy-entropy compensation and, together with the NMR spectroscopic analysis of the separate species, non-cooperative binding is conceived to be the most probable binding scenario. The binding behavior of CB[8] homoternary complexes is similar to CB[8] heteroternary complexes, with an enthalpy-driven tight fit of the guests in the CB[8] cavity overcoming the entropic penalty. Also for these types of complexes, a non-cooperative binding is the most probable.
authors.affiliation: Department of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Cavatorta
authors.affiliation: Department of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
authors.forename: Pascal
authors.identifier: http://orcid.org/0000-0001-6271-0049
authors.initials: P
authors.lastname: Jonkheijm
authors.affiliation: Department of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.
authors.forename: Jurriaan
authors.identifier: http://orcid.org/0000-0002-4596-9179
authors.initials: J
authors.lastname: Huskens
mesh_terms: D001952:Bridged-Ring Compounds / Q000737:chemistry*; D002151:Calorimetry / Q000379:methods; D007093:Imidazoles / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D010455:Peptides / Q000737:chemistry*; D011485:Protein Binding; D013816:Thermodynamics; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
chemical_list: D001952:Bridged-Ring Compounds; D007093:Imidazoles; D008024:Ligands; D010455:Peptides; C507198:cucurbit(8)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
keywords: complexation; cooperativity; cucurbit[n]uril; self-assembly; titration