Timmins P A, Hauk J, Wacker T, Welte W
Institut Laue Langevin, Grenoble, France.
FEBS Lett. 1991 Mar 11;280(1):115-20. doi: 10.1016/0014-5793(91)80217-q.
The presence of small amphiphiles has been found to be necessary in the crystallization of several membrane-protein/surfactant complexes. It has been suggested that the role of the small amphiphile may be to reduce the size of the surfactant belt around the protein, making the formation of crystals easier. Thus far it was not known if this would involve changes in micellar size in general or whether the small amphiphile would merely replace LDAO during crystal growth. In the present study we have used small angle neutron scattering to study mixed micelles of lauryldimethyl amine oxide (LDAO; hydrogenated and deuterated) and heptane-1,2,3-triol (HP). Our results show that with increasing overall HP concentrations mixed LDAO/HP micelles of decreasing mass and radius are formed. The composition of these micelles has been determined. HP thus may decrease the size of the surfactant belt around a protein before crystallisation by insertion into a host micelle. As HP is a 'small amphiphile' compared to the surfactants used for solubilization of membrane proteins, the curvature of the host micelle will be increased by its insertion.
已发现小两亲物的存在对于几种膜蛋白/表面活性剂复合物的结晶是必要的。有人提出，小两亲物的作用可能是减小蛋白质周围表面活性剂带的尺寸，从而使晶体形成更容易。到目前为止，尚不清楚这是否一般会涉及胶束尺寸的变化，或者小两亲物是否仅仅在晶体生长过程中取代月桂基二甲基氧化胺（LDAO）。在本研究中，我们使用小角中子散射来研究月桂基二甲基氧化胺（LDAO；氢化和氘化）与1,2,3 - 庚三醇（HP）的混合胶束。我们的结果表明，随着HP总浓度的增加，形成了质量和半径减小的混合LDAO/HP胶束。已确定了这些胶束的组成。因此，HP可能在结晶前通过插入主体胶束来减小蛋白质周围表面活性剂带的尺寸。由于与用于溶解膜蛋白的表面活性剂相比，HP是一种“小两亲物”，其插入会增加主体胶束的曲率。
