Molecular Dynamics Simulation Study Of The Antibacterial Mechanism Of Antimicrobial Peptide Gaegurin4 And Interaction Study Of Pesticides With Cyclodextrins

The antibacterial mechanism of the antimicrobial peptide gaegurin4 and the interactions betweenβ-cyclodextrin(β-CD),2-hydroxyropyl-β-cyclodextrin(HP-β-CD) and pesticides(azoxystrobin,Y5247 and flumetsulam) have been investigated using molecular dynamics simulations and high resolution nuclear magnetic resonance(NMR) techniques,the details are as follows:1.We have performed molecular dynamics simulations ofα-helical amphipathic antimicrobial peptide gaegutin4(GGN4) in both water and palmitoyl-oleoyl-phosphatidylcholine (POPC) lipid bilayers environment using GROMACS program. Results show that the secondary structure of GGN4 incurs an obvious loss in aqueous solution,which is completely consistent with the NMR observation that secondary structure can not stablely exist in aqueous solution.While molecular dynamics simulations of peptide in POPC and POPC/water interface indicate that GGN4 has a trend permeating to the internal of lipid bilayer.Furthermore,we also observed that the hydrogen bonding interactions between the threonine,lysines of the peptide and the lipid head-group region play an important role in the interaction of peptide with POPC lipid bilayer.2.The interactions of some pesticides including azoxystrobin,Y5247 and flumetsulam(guest molecules) with cyclodextrin includingβ-CD,HP-β-CD(host molecules) in DMSO solution have been investigated using NMR techniques,especially two-dimensional rotating frame nuclear Overhauser effect spectroscopy(ROESY) and correlation spectroscopy(COSY) experiments,and possible conformations of the inclusion complex have been proposed.That is,the size of the guests has an obvious impact on inclusion,and moreover,the guest/host stoiehiometry of flumetsulam/ Cylcodextrin inclusion complex could be 1:1,and different aromatic rings of the flumetsulam molecule could be alternatively included in the CDs cavity because the host-guest inclusion can be considered as a dynamical process.