松木均先生らの論文「FTIR Study of Temperature- and Pressure-Induced Phase Transitions and Intermolecular Interaction Changes in DMPC Bilayers in H2O and D2O」が掲載されました。

 

掲載誌等：Bulletin of the Chemical Society of Japan, 98, 12, uoaf105, 2025.
DOI：10.1093/bulcsj/uoaf105
著者：Toshiki Nakao, Hitoshi Matsuki and Minoru Kato

 

要約：The thermodynamic and microscopic characteristics of membrane states accompanying temperature-induced phase transitions in phospholipid bilayer membranes forming liposomes have been well elucidated in previous studies. However, microscopic insights into membrane states during pressure-induced phase transitions particularly changes in intermolecular interactions between phospholipid molecules remain limited. In this study, we analyzed such interactions in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) bilayer membranes using temperature-variable and pressure-variable infrared (IR) spectroscopy in both H2O and D2O environments. We focused on symmetric and antisymmetric stretching modes of methylene (νs(CH2), νas(CH2)) and methyl groups (νs(CH3), νas(CH3)), which effectively reflect molecular interactions. Frequency shifts in these vibrational modes correlated well with membrane curvature and solvent-induced changes in gel phase packing. Temperature and pressure derivatives ∂ν/∂P provided insight into bilayer stability across phases. In particular, ∂ν/∂P for νs(CH2) was about half as large in the interdigitated gel (LβI) phase as in the lamellar gel (Lβ’) phase, suggesting reduced repulsive interactions between methylene chains in the LβI phase.

 

キーワード：Phospholipid bilayer / 赤外分光法 (infrared spectroscopy) / 相転移 (phase transition)