A low-temperature structural phase transition in aqueous dimyristoyl phosphatidylcholine bilayers observed by Raman scattering

A new structural phase change at 1260 \ub0C and atmospheric pressure was observed in the gel phase of aqueous DMPC dispersions. This gel\u2013gel phase transition exhibits first-order characteristics and is equivalent to the phase transition observed at 2.6\u2002kbar and 30 \ub0C. The decrease in temperature has analogous effects on the ordering of the acyl chains in DMPC as has the increase in pressure. The rigid interchain reorientational fluctuations in the gel phase are gradually damped with decreasing temperature and below 1260 \ub0C the interchain orientation becomes highly ordered.On a observ\ue9 un nouveau changement structural de phase \ue0 60 \ub0C et \ue0 la pression atmosph\ue9rique dans la phase gel des dispersions aqueuses du CDMP. Cette transition de phase gel\u2013gel a des caract\ue9ristiques d'ordre un et \ue9quivaut \ue0 la transition de phase observ\ue9e \ue0 2,6\u2002kbar et \ue0 30 \ub0C. La diminution de temp\ue9rature a des effets analogues sur l'agencement des cha\ueenes acyles du CDMP lorsque la pression augmente. Les fluctuations dans la r\ue9orientation entre cha\ueenes rigides de la phase gel sont amorties graduellement lorsque la temp\ue9rature diminue; et en-dessous de 1260 \ub0C, l'orientation entre les interchaines devient fortement ordonn\ue9e.Peer reviewed: YesNRC publication: Ye