Skip navigation
Run Run Shaw Library City University of Hong KongRun Run Shaw Library

Please use this identifier to cite or link to this item: http://dspace.cityu.edu.hk/handle/2031/9124
Title: Microscopic insights into melittin induced changes in molecular dynamics of lipid bilayer membranes
Authors: Jiang, Huanbo (江煥波)
Department: Department of Physics
Issue Date: 2018
Course: AP4217 Dissertation
Programme: Bachelor of Science (Honours) in Applied Physics
Supervisor: Dr Fan, Jun
Citation: Jiang, H. (2018). Microscopic insights into melittin induced changes in molecular dynamics of lipid bilayer membranes (Outstanding Academic Papers by Students (OAPS), City University of Hong Kong).
Abstract: Melittin is an important antimicrobial peptide, and its membrane disruption mechanism has been attributed to its strong interaction with the cell membrane. Recently, Sharma et al. have investigated effects of melittin on the dynamics of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) membrane using neutron scattering techniques. Their measurements showed that effects of melittin strongly depend on the physical state of the bilayers and the presence of cholesterol. In this study, extensive molecular dynamics (MD) simulations are performed on the DMPC lipid bilayers with and without cholesterol in the range of temperatures 275-315 K to investigate the effects of melittin on the microscopic dynamics of the membrane. Through the decomposition of membrane dynamics, our MD simulations suggest that in the fluid phase, the nanoscale membrane dynamics observed in the neutron experiments arises primarily from lateral diffusion, while in the gel phase, local internal motion plays an important role, accounting for 43.3%~60.7% of the total mean square displacement (MSD). Due to the different nature of the lateral diffusion and the local internal motion, how melittin affects the apparent membrane dynamics thus highly depends on the phase state of the membrane. In the fluid phase DMPC, the addition of melittin disrupts the lateral diffusion motion, leading to the overall hindered dynamics observed in experiment. However, the addition of melittin enhances the local internal motion slightly in the gel phase DMPC, giving rise to the apparent faster dynamics observed in experiment. In contrast, when 20% cholesterol is present, the bilayer abolishes the gel to fluid transition, the lateral diffusion is greatly suppressed across the entire experimental temperature range, exhibiting negligible differences in the membrane dynamics when melittin is added. Taken together, our simulations provide a unified mechanism for the effects of melittin on the DMPC bilayer dynamics both with and without cholesterol.
Appears in Collections:OAPS - Dept. of Physics 

Files in This Item:
File SizeFormat 
fulltext.html153 BHTMLView/Open
Show full item record


Items in Digital CityU Collections are protected by copyright, with all rights reserved, unless otherwise indicated.

Send feedback to Library Systems
Privacy Policy | Copyright | Disclaimer