Stability and structures of liquid crystalline phases formed by branched-chain phospholipid diastereomers

被引:3
作者
Bringezu, F [1 ]
Rapp, G
Dobner, B
Nuhn, P
Brezesinski, G
机构
[1] Univ Calif Santa Barbara, Dept Chem Engn Engn 2, Santa Barbara, CA 93106 USA
[2] Max Planck Inst Colloids & Interfaces, D-14476 Golm, Germany
[3] Univ Halle Wittenberg, Inst Pharmaceut Chem, D-06099 Halle, Germany
关键词
D O I
10.1021/jp0042720
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Diastereomers of 1-alkyl-2-acylglycerophosphocholines containing 2-methyl-branched fatty acids at the C2 position of the glycerol are synthesized and separated, varying the acyl-chain systematically (m = 13, 15, 17). The physicochemical properties are studied in monolayers at the air-water interface by pressure area isotherms and grazing incidence X-ray diffraction (GIXD) measurements. The phase behavior is examined by a combination of differential scanning calorimetry and time-resolved X-ray diffraction experiments, In monolayers at the air-water interface, the introduction of a methyl-branch disturbs the lateral packing drastically, resulting in phases with strongly tilted chains and an undefined tilt azimuth. The monolayer structures of the diastereomeric fractions cannot be distinguished. The comparison of the lyotropic mesophases of the aqueous dispersions shows comparable structural parameters. The temperature dependency of the d spacings is nonlinear and is discussed in terms of a critical swelling of the bilayer. The present experiments show that the two racemic pairs of the resolved diastereomers (SS + RR/SR + RS) exhibit pronounced differences in the thermodynamic parameters of phase transitions both in two-dimensional (monolayers at the air/water interface) and three-dimensional systems (aqueous dispersions). However, the influence of the chiral carbon atoms is not sufficient to change the structure of the phases despite being able to affect their stability.
引用
收藏
页码:1901 / 1907
页数:7
相关论文
共 39 条
[31]   Sterols sense swelling in lipid bilayers [J].
Richter, F ;
Finegold, L ;
Rapp, G .
PHYSICAL REVIEW E, 1999, 59 (03) :3483-3491
[32]  
SELINGER Z, 1966, J LIPID RES, V7, P174
[33]   Ordering in Langmuir monolayers of branched chain phospholipids [J].
Siegel, S ;
Vollhardt, D ;
Brezesinski, G ;
Bringezu, F ;
Möhwald, H .
MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS, 1999, 8-9 :3-11
[34]  
SMALL DM, 1986, HDB LIPID RES, V4, P475
[35]   The preparation of certain octadecanoic acids and their bactericidal action toward B leprae XV [J].
Stanley, WM ;
Jay, MS ;
Adams, R .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1929, 51 (1-4) :1261-1266
[36]  
Stritzel R, 1996, HRC-J HIGH RES CHROM, V19, P121
[37]   Disorder in Langmuir monolayers. 1. Disordered packing of alkyl chains [J].
Weidemann, G ;
Brezesinski, G ;
Vollhardt, D ;
Mohwald, H .
LANGMUIR, 1998, 14 (22) :6485-6492
[38]  
WEITZEL G, 1950, HOPPESEYLER Z PHYSL, V285, P221
[39]   CRITICAL FLUCTUATIONS IN MEMBRANES [J].
ZHANG, RT ;
SUN, WJ ;
TRISTRAMNAGLE, S ;
HEADRICK, RL ;
SUTER, RM ;
NAGLE, JF .
PHYSICAL REVIEW LETTERS, 1995, 74 (14) :2832-2835