Effect of the chirality of the glycerol backbone on the bilayer and nonbilayer phase transitions in the diastereomers of di-dodecyl-beta-D-glucopyranosyl glycerol.
Effect of the chirality of the glycerol backbone on the bilayer and nonbilayer phase transitions in the diastereomers of di-dodecyl-beta-D-glucopyranosyl glycerol.
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甘油主链的手性对二十二烷基-β-D-吡喃葡萄糖基甘油非对映体双层和非双层相变的影响。
DOI：
10.1016/s0006-3495(92)81713-7
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发表时间：
1992
影响因子：
3.4
通讯作者：
Gruner,SM
中科院分区：
文献类型：
--
作者：
Mannock,DA;Lewis,RN;McElhaney,RN;Akiyama,M;Yamada,H;Turner,DC;Gruner,SM
用差示扫描量热法和小角X射线衍射法研究了1，2-SN和2，3-SN-二十二烷基β-D-吡喃葡萄糖甘油及其非对映异构体混合物的水分散体的物理性质。加热时，手性脂类和非对映异构体混合物在31.7-32.8℃发生特征高能Lβ/Lα相变，在49-89℃之间发生两到三个弱能热事件。在非对映异构体混合物和1，2-sn甘油衍生物中，这些较高的吸热对应于几个非片层结构的形成和相互转化，并分别被归属为Lα/QIIa、QIIa/QIIb和QIIb/HII相变。立方相QIIa和QIIb的晶胞参数与温度密切相关，分别属于空间群Ia3d和Pn3m/Pn3。在相当的2，3-sn糖脂中，没有观察到QIIa相，在49℃和77℃只观察到两个相变，分别被鉴定为Lα/QIIb和QIIb/HII相变。这些相变温度比在非对映异构体混合物和1，2-sn甘油衍生物中观察到的相应相变温度低约10摄氏度。冷却时，三种脂类都表现出一个较小的较高温度放热事件，可归结为HII/QIIb相变。在30-31℃观察到一个放热的Lα/Lβ相变，在Lα/Lβ事件的高温侧有时可以看到肩部，这可能起源于烃链冻结之前的QIIb/Lα相变。所有的脂类都没有显示出冷却的QIIa阶段的证据。在进一步冷却到-3℃时没有观察到额外的放热转变。然而，在0℃成核之后在22℃短暂的热处理后，1，2-sn糖脂形成LC相，该相在39.5℃加热时转变为Lα相。即使在长时间的退火期后，非对映异构体混合物和2，3-sn甘油衍生物也不会表现出这样的行为。我们的结果表明，这些糖脂异构体相行为的差异可能不是由于头基本身的大小，而是由于脂极性/非极性界面区域的立体化学的差异，从而影响氢键、水化和亲水/疏水平衡。
We have studied the physical properties of aqueous dispersions of 1,2-sn- and 2,3-sn-didodecyl-beta-D-glucopyranosyl glycerols, as well as their diastereomeric mixture, using differential scanning calorimetry and low angle x-ray diffraction. Upon heating, both the chiral lipids and the diastereomeric mixture exhibit characteristically energetic L beta/L alpha phase transitions at 31.7–32.8 degrees C and two or three weakly energetic thermal events between 49 degrees C and 89 degrees C. In the diastereomeric mixture and the 1,2-sn glycerol derivative, these higher temperature endotherms correspond to the formation of, and interconversions between, several nonlamellar structures and have been assigned to L alpha/QIIa, QIIa/QIIb, and QIIb/HII phase transitions, respectively. The cubic phases QIIa and QIIb, whose cell lattice parameters are strongly temperature dependent, can be identified as belonging to space groups Ia3d and Pn3m/Pn3, respectively. In the equivalent 2,3-sn glucolipid, the QIIa phase is not observed and only two transitions are seen at 49 degrees C and 77 degrees C, which are identified as L alpha/QIIb and QIIb/HII phase transitions, respectively. These phase transitions temperatures are some 10 degrees C lower than those of the corresponding phase transitions observed in the diastereomeric mixture and the 1,2-sn glycerol derivative. On cooling, all three lipids exhibit a minor higher temperature exothermic event, which can be assigned to a HII/QIIb phase transition. An exothermic L alpha/L beta phase transition is observed at 30–31 degrees C. A shoulder is sometimes discernible on the high temperature side of the L alpha/L beta event, which may originate from a QIIb/L alpha phase transition prior to the freezing of the hydrocarbon chains. None of the lipids show evidence of a QIIa phase on cooling. No additional exothermic transitions are observed on further cooling to -3 degrees C. However, after nucleation at 0 degrees C followed by a short period of annealing at 22 degrees C, the 1,2-sn glucolipid forms an Lc phase that converts to an L alpha phase at 39.5 degrees C on heating. Neither the diastereomeric mixture nor the 2,3-sn glycerol derivative shows such behavior even after extended periods of annealing. Our results suggest that the differences in the phase behavior of these glycolipid isomers may not be attributable to headgroup size per se, but rather to differences in the stereochemistry of the lipid polar/apolar interfacial region, which consequently effects hydrogen-bonding, hydration, and the hydrophilic/hydrophobic balance.
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DOI：
--
发表时间：
1988
期刊：
Biochimica et Biophysica Acta
影响因子：
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DOI：
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发表时间：
1984
期刊：
影响因子：
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作者：
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DOI：
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发表时间：
1990
期刊：
影响因子：
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作者：
J. Seddon;J. Hogan;N. A. Warrender;E. Pebay‐Peyroula
通讯作者：
E. Pebay‐Peyroula
影响因子：
2.9
作者：
Sen,A;Hui,SW;Mannock,DA;Lewis,RN;McElhaney,RN
通讯作者：
McElhaney,RN
影响因子：
3.4
作者：
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通讯作者：
SUNDELL, S