Quantum-mechanical simulations of inclusion compounds: Cyclodextrine and
polypeptides in aqueous solution

Hélio A. Duarte, duarteh@ufmg.br, Department of Chemistry, Universidade Federal
de Minas Gerais - UFMG, Av. Antonio Carlos, 6627, Belo Horizonte - MG,
31270-901, Brazil, Serguei Patchkovskii, Serguei.Patchkovskii@nrc.ca, Department
of Chemistry, Steacie Institute for Molecular Sciences, Sussex Dr. 100, Ottawa,
ON T2N 1N4, Canada, Hélio F. Dos Santos, helius@quimica.ufjf.br, Department of
Chemistry, Universidade Federal de Juiz de Fora, Juiz de Fora - MG, 36036-900,
Brazil, and Thomas Heine, thomas.heine@chemie.tu-dresden.de, Physikalische
Chemie, Technische Universität Dresden, Dresden, D-01062, Germany.

ß-cyclodextrine (ß-CyD) and its inclusion compound with angiotensine (1-7)
(ANG(1-7)) in aqueous solution have been investigated by means of QM/MM hybrid
methods. The QM part has been treated with DFTB including second-order density
correction scheme and the correction for London dispersion (DC-SCC-DFTB), in the
MM part Rappé's universal force field (UFF) is employed. Born-Oppenheimer
Molecular Dynamics trajectories of the whole system, containing up to 275 QM
atoms and 7456 water molecules of 0.2 ns were carried out. The flexibility of
the structures, the dynamics of encapsulated water molecules in ß-CyD, the
conformation of ANG (1-7) in water and the formation of the ß-CyD:ANG(1-7)
inclusion compound via tyrosine residue in aqueous solution are discussed.