Behavior of head groups in phospholipids at phase transition

磷脂中头基在相变时的行为

• 批准号: 09640486
• 负责人: UTOH Shigenori
• 金额: $ 2.05万
• 依托单位: Fukuoka University of Education
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640486/
• 关键词: phospholipid; head group; sub transition; super cooled water; x-ray diffraction; Raman scattering; hydrocarbon chain packing; high pressure; x-ray回折; WAXS; SAXS; DSPC; DMPC

1. Under high pressure the sub transition, which is composed of two reversible phenomena, i.e., the 4th and 3rd transitions, is obtained from the sample which is conditioned by the high pressure melting. The motion of head group, i.e., choline, phosphoric acid, glycerine, and acyl parts of priospholipids, is monitored at the 4th and 3rd transition by Raman scattering methods, which is verified head groups closely take part in the sub transition.2. Dehydration of head group, i.e., changes from water or super cooled water' to ice', promotes movements of head group and those of hydrocarbon chain connected with it. it is also verifies that conditions, which is surrounded by two parallel plates of head groups, obstruct the growth of ice, i.e., the state of super cooled water continues down to extremely low temperature (e.g., -45 C in the case of DSPC contained 15 wt% water).3. In cooling process super cooled water in the excess water and the water layer between phospholipids bilayer in multilamellar freezes at -2OﾟC and 45ﾟC , respectively, where the excess water means the extra water besides water layer in multilamellar. Each case shows homogeneous or heterogeneous ice conformation with hexagonal symmetry in the excess water or the water layer, respectively.4. The sub transition appears without special condition, e.g., the long-term cooling process under A2. as like keeping phospholipids around 4ﾟC for more than 72 hours, using some kinds of phospholipids having C_n=2O, 22 and 24/chain. In these cases two phenomena, which closely corresponds to the 4th and 3rd transitions under high pressure, compose the sub transition and occur reversibly.

1.在高压下，亚转变由两种可逆现象组成，即，第4和第3次转变，是从高压熔融处理的样品中获得的。头群的运动，即，通过拉曼散射方法监测了磷脂中胆碱、磷酸、甘油和酰基部分的第4和第3跃迁，证实了头基密切参与了次跃迁.头基脱水，即，由水或过冷水“冰”化，促进了头基及其所连接的烃链的运动，也证实了由头基的两个平行板所包围的条件阻碍了冰的生长，即，过冷水的状态继续下降到极低的温度（例如，在DSPC含有15wt%水的情况下为-45 ℃）。在冷却过程中，过量水中的过冷水和多层膜中磷脂双层之间的水层分别在-20 ℃和45 ℃下冻结，其中过量水是指多层膜中除水层之外的额外水。每种情况下，在过量水或水层中分别表现出六角对称的均匀或非均匀冰形态.子转换出现时没有特殊条件，例如，A2下的长期冷却过程。如用C_n= 20、22和24/链的磷脂在4 ℃下保存72小时以上。在这些情况下，两种现象，这密切对应于高压下的第四和第三转变，组成子转变，并可逆地发生。

项目成果

Shigenori UTOH: "Changes of Hydrocarbon Chains and Head Groups in Distearoyl Phosphatidylcholine at 4th and 3rd Transition under High Pressure" Japanese Journal of Applied Physics. Vol.38 No.4A. (1999)

Shigenori UTOH：“高压下第四次和第三次转变时二硬脂酰磷脂酰胆碱中烃链和头基的变化”日本应用物理学杂志。

Shigenori UTOH: "Changes of Hydrocarbon Chalns and Head Groups in Distearoyl Phosphatidylchollne at 4th and 3rd Transition under High Pressure" Japanese Journal of Applied Physics. Vol.38, No.4A. (1999)

Shigenori UTOH：“高压下第四次和第三次转变时二硬脂酰磷脂酰胆碱中烃链和头基的变化”日本应用物理学杂志。

Shigenori UTOH: "Changes in Hydrocarbon Chains and Head Groups in Distearoyl Phosphatidylcholine at 4th and 3rd Transition under High Pressure" Japanese Journal of Applied Physics. Vol.38 Part1 No.4A. (1999)

Shigenori UTOH：“高压下第四次和第三次转变时二硬脂酰磷脂酰胆碱中烃链和头基的变化”日本应用物理学杂志。