Abstract
Aquaporins are water-permeable membrane-channel proteins found in biological cell membranes that selectively exclude ions and large molecules and have high water permeability, which makes them promising candidates for water desalination systems. To effectively apply the properties of aquaporins in the desalination process, many studies have been conducted on aquaporin-lipid membrane systems using phospholipids, which are the main component of cell membranes. Many parametric studies have evaluated the permeability of such systems with various aquaporin types and lipid compositions. In this study, we performed molecular dynamics simulations for four cases with different protein-lipid molar ratios (1:50, 1:75, 1:100, and 1:150) between aquaporin Z and the phospholipids, and we propose a possibility of the existence of optimal protein-lipid molar ratio to maximize water permeability. Elucidating these simulation results from a structural viewpoint suggests that there is a relationship between the permeability and changes in the hydrophobic thickness of the lipid membrane adjacent to the aquaporin as a structural parameter. The results of this study can help optimize the design of an aquaporin-lipid membrane by considering its molar ratio at an early stage of development.
Highlights
With global population growth and climate changes, water purification techniques have gained much attention to overcome water shortages
Aggregation does not occur on the scale of molecular dynamics (MD) simulation, but for consistency with the lipid system used in experimental studies, the mixture of phosphatidylcholine and phosphatidylglycerol was adopted as a model
When a membrane protein is inserted into a lipid membrane, the difference between the hydrophobic thickness of the membrane protein and the hydrophobic thickness of the lipid membrane adjacent to the membrane protein makes the thickness of membrane deformed to become closer to the hydrophobic thickness of the membrane protein
Summary
With global population growth and climate changes, water purification techniques have gained much attention to overcome water shortages. Among the commercialized membrane-based methods for water purification, the most widely used technique is reverse osmosis (RO), which applies external pressure to a porous filtration membrane separating contaminated water and freshwater. An RO membrane is not applicable when the system requires desalination of high-salinity solutions and/or high recovery rates. The forward osmosis (FO) technique exploits the osmosis of highly concentrated draw solutions and pure water [1] because an FO membrane does not require external pressure to overcome the osmotic gradient. The FO method still demands further development to achieve high permeability for widespread use in commercialized products.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
