Interaction of anesthetic molecules with α-helix and polyproline II extended helix of long-chain poly-L-lysine

The effect of halothane, enflurane, sevoflurane, and isoflurane molecules, as volatile anesthetics, on the alpha-helices and polyproline II extended helices (PPII) of long-chain poly-L-lysine (PLL) were studied using Fourier-transform infrared and vibrational circular dichroism spectroscopy. Uncharged and charged alpha-helices, as well as charged extended PPII helices, were subjected to anesthetic actions in solvents with different pD values or methanol to water ratios. A crucial factor responsible for hindering the anesthetic-PLL interactions is shown to be the ionization of amino groups of the PLL side chains. The alpha-helix to beta-sheet transition was triggered only for the uncharged alpha-helical structures of PLL by the nonpolar anesthetics under study. (C) 2017 Elsevier B.V. All rights reserved.