Effects of aquaporin-lipid molar ratio on the permeability of an aquaporin Z-phospholipid membrane system

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.

Membrane nanodomains and transport functions in plant

“…Especially the ratio between phospholipids and proteins was shown to modify the water permeability induced by these aquaporins. This supposes that protein lipid hydrophobicity matching acts on aquaporin activity (Kim et al, 2020). In addition, AQP4 and AQP2 activities are tightly linked to cholesterol concentration in the membrane (Tong et al, 2012(Tong et al, , 2013.…”

Aquaporin‐Based Biomimetic Membranes for Low Energy Water Desalination and Separation Applications

“…The mismatch between the hydrophobic length of AQP proteins and the hydrophobic thickness of the lipid membrane leads to membrane deformation, reducing membrane flexibility and the AQP proteins' function. [99] Zhao et al [83] systematically evaluated the influence of lipid type on the properties of AqpZ-based proteoliposomes. The water permeability of five AqpZ-based lipids, including E. coli total extract lipids, DOPC, DPhPC, DOPG, and DOTAP, was evaluated.…”