Program

Poster Presentations

Day 3, May 17（Thu.）　　Poster

3P-22　　PDF

Programming Water Transporter Aquaporin Z by Lipid Composition-Altered Protein Dynamics

(NUS)
^oXin Shan Lim, Ganesh Anand, Qingsong Lin

Aquaporins (AQPs) are ubiquitous integral membrane water channel proteins that performs bidirectional water transport in many different cells and are fabricated into AQP biomimetic membranes for desalination applications. In vitro water permeability measurements of different AQP isoforms has consistently illustrated their membrane specific water permeability which highlights the role of phospholipid membranes as critical regulators of AQP mediated water transport. While functionally distinct, solved structures of AQPs embedded in different membranes showed no significant difference. As such, we have adopted a thermodynamic characterization of AQPz (E.coli AQP) using amide hydrogen-deuterium exchange mass spectrometry (HDXMS). Using the extent of HDX on peptides of AQPz as thermodynamic probes, our results illustrated that AQPZ adopts distinct thermodynamics and water permeability under three different membrane environments (DOPC, 3DOPC:1DOPG and E.coli lipid). Correlating the protein dynamics to function, it is apparent that fine balance between structural stability and fluidity is required for highest water permeability. These findings illustrates that by understanding the protein-lipid interactions between AQPz and its phospholipid membrane, it is possible to program the water permeability of AQPz by altering membrane composition. This allows selection of optimal membrane matrix during the fabrication of AQP biomimetic membranes.