Mosaic of Water Orientation Structures at a Neutral Zwitterionic Lipid/Water Interface Revealed by Molecular Dynamics Simulations.
Ordering of water structures near the surface of biological membranes has been recently extensively studied using interface-selective techniques like vibrational sum frequency generation (VSFG) spectroscopy. The detailed structures of interface water have emerged for charged lipids, but those for neutral zwitterionic lipids remain obscure. We analyze an all-atom molecular dynamics (MD) trajectory of a hydrated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer to characterize the orientation of interface waters in different chemical environments. The structure and dynamics of interfacial waters strongly depend on both their vertical position along the bilayer normal as well as vicinal lipid charged groups. Water orientation in the vicinity of phosphate groups is opposite to that around choline groups. The results are consistent with observed VSFG spectra and demonstrate that a mosaic of water orientation structures exists on the surface of a neutral zwitterionic phospholipid bilayer, reflecting rapid water exchange and the influence of local chemical environments.
†RIKEN Theoretical Molecular Science Laboratory, ‡Molecular Spectroscopy Laboratory, §Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), and ¶RIKEN iTHES, RIKEN , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.|#RIKEN Advanced Institute for Computational Science and ⊥RIKEN Quantitative Biology Center, International Medical Device Alliance (IMDA) 6F, RIKEN, 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
Suyong
S
Re
†RIKEN Theoretical Molecular Science Laboratory, ‡Molecular Spectroscopy Laboratory, §Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), and ¶RIKEN iTHES, RIKEN , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.|#RIKEN Advanced Institute for Computational Science and ⊥RIKEN Quantitative Biology Center, International Medical Device Alliance (IMDA) 6F, RIKEN, 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
Wataru
W
Nishima
†RIKEN Theoretical Molecular Science Laboratory, ‡Molecular Spectroscopy Laboratory, §Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), and ¶RIKEN iTHES, RIKEN , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.|#RIKEN Advanced Institute for Computational Science and ⊥RIKEN Quantitative Biology Center, International Medical Device Alliance (IMDA) 6F, RIKEN, 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
Tahei
T
Tahara
†RIKEN Theoretical Molecular Science Laboratory, ‡Molecular Spectroscopy Laboratory, §Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), and ¶RIKEN iTHES, RIKEN , 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.|#RIKEN Advanced Institute for Computational Science and ⊥RIKEN Quantitative Biology Center, International Medical Device Alliance (IMDA) 6F, RIKEN, 1-6-5 minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
Yuji
Y
Sugita
interfacial water; molecular dynamics simulation; mosaic of water orientation structures; water orientation; zwitterionic POPC/water interface