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Talanta. 2018 Aug 15;186:1-7. doi: 10.1016/j.talanta.2018.04.003. Epub 2018 Apr 3.

Gas-phase complexation of α-/β-cyclodextrin with amino acids studied by ion mobility-mass spectrometry and molecular dynamics simulations.

Author information

1
School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; Collaborative Innovation Center of Chemistry for Energy Materials(iChEM), Shanghai Key Laboratory of Molecular Catalysis and Functional Material, Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai 200433, China.
2
Collaborative Innovation Center of Chemistry for Energy Materials(iChEM), Shanghai Key Laboratory of Molecular Catalysis and Functional Material, Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai 200433, China.
3
Chemical Metrology & Analytical Science Division, National Institute of Metrology, Beijing 100013, China.
4
School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
5
Collaborative Innovation Center of Chemistry for Energy Materials(iChEM), Shanghai Key Laboratory of Molecular Catalysis and Functional Material, Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai 200433, China. Electronic address: wnwang@fudan.edu.cn.
6
Collaborative Innovation Center of Chemistry for Energy Materials(iChEM), Shanghai Key Laboratory of Molecular Catalysis and Functional Material, Department of Chemistry and Laser Chemistry Institute, Fudan University, Shanghai 200433, China. Electronic address: cfding@fudan.edu.cn.

Abstract

Cyclodextrins (CDs) are a class of macrocyclic molecules that have exhibited many promising applications in various fields. The knowledge of the complexation modes and recognition mechanisms of CDs with their guests are of paramount importance for rational design of more variants with controlled properties. Herein we investigated the binding conformations and the structural characteristics of α-/β-CD with three amino acids (AA, AA=Gly, L-Leu, L-Phe) in the gas phase by a combined experimental and computational approach. Electrospray ionization-mass spectrometry suggested the formation of 1:1 anionic complexes between CDs and AAs and the complex anions were further identified by tandem mass spectrometry. Moreover, ion mobility-mass spectrometry experiments revealed the inclusion complexation adopted for [α-CD+Gly]- as well as β-CD with either amino acid, whereas [α-CD+Leu]- and [α-CD+Phe]- favored an exclusion conformation, indicating size-dependent binding modes. The association is primarily driven by polar interactions via the formation of hydrogen bonds. Furthermore, the relative dynamic stabilities of the complex ions were observed to be in correlation with the gas-phase basicities of the deprotonated amino acid and CD anions. These above findings are well in line with our atomistic molecular dynamics simulation results. This study advances our understanding of the mechanisms underlying CD host-guest recognition.

KEYWORDS:

Amino acids; Cyclodextrin; Exclusion; Inclusion; Ion mobility-mass spectrometry; Molecular dynamics simulation

PMID:
29784335
DOI:
10.1016/j.talanta.2018.04.003
[Indexed for MEDLINE]

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