Gruner S M
Proc Natl Acad Sci U S A. 1985 Jun;82(11):3665-9. doi: 10.1073/pnas.82.11.3665.
A rationale is presented for the mix of "bilayer" and "nonbilayer" lipids, which occurs in biomembranes. A theory for the L alpha-HII phase transition and experimental tests of the theory are reviewed. It is suggested that the phase behavior is largely the result of a competition between the tendency for certain lipid monolayers to curl and the hydrocarbon packing strains that result. The tendency to curl is quantitatively given by the intrinsic radius of curvature, Ro, which minimizes the bending energy of a lipid monolayer. When bilayer (large Ro) and nonbilayer (small Ro) lipids are properly mixed, the resulting layer has a value of Ro that is at the critical edge of bilayer stability. In this case, bilayers may be destabilized by the protein-mediated introduction of hydrophobic molecules, such as dolichol. An x-ray diffraction investigation of the effect of dolichol on such a lipid mixture is described. This leads to the hypothesis that biomembranes homeostatically adjust their intrinsic curvatures to fall into an optimum range. Experimental strategies for testing the hypothesis are outlined.
本文阐述了生物膜中“双层”和“非双层”脂质混合存在的基本原理。回顾了关于Lα-HII相变的理论及其实验验证。研究表明，相行为主要是某些脂质单分子层卷曲趋势与由此产生的烃类堆积应变之间竞争的结果。卷曲趋势由固有曲率半径Ro定量给出，Ro可使脂质单分子层的弯曲能量最小化。当双层（大Ro）和非双层（小Ro）脂质适当混合时，所得层的Ro值处于双层稳定性的临界边缘。在这种情况下，双层可能会因蛋白质介导引入疏水分子（如多萜醇）而失稳。描述了一项关于多萜醇对这种脂质混合物影响的X射线衍射研究。由此提出一个假设，即生物膜通过自我调节其固有曲率以落入最佳范围。概述了验证该假设的实验策略。
