The binding behaviours between cyclopentanocucurbit[6]uril and three amino acids
Siyuan Cheng1, Weiwei Zhao1, Xinan Yang1
1Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang 550025, People's Republic of China.
Abstract:
Binding behaviours between cyclopentanocucurbit[6]uril (CyP6Q[6]) and three amino acids have been investigated by means of X-ray crystallography, proton nuclear magnetic resonance spectroscopy and isothermal titration calorimetry. The results showed that CyP6Q[6] forms a 1 : 2 inclusion complex with glycine, but 1 : 1 complexes with both leucine and lysine. Whereas the carboxyl group of glycine can enter the interior of the cavity of CyP6Q[6], only the alkyl chains of leucine and lysine can enter this cavity. Interestingly, leucine can adopt two different self-assembly modes upon its interaction with cucurbituril, depending on the external conditions, whereas glycine and lysine do not exhibit such behaviour.
Related Concept Videos
Conformations of Cyclohexane
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
Chair Conformation of Cyclohexane
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
Stability of Substituted Cyclohexanes
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
Conformations of Cycloalkanes
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group...
Criteria for Aromaticity and the Hückel 4n + 2 Rule
For the first time, Eric Hückel, a German chemical physicist, derived a set of structural features for a compound to be classified as aromatic. This is now known as Hückel’s rule or the 4n +...


