STRUCTURAL STUDIES OF DEHYDROGENASES AND LIPOPROTEINS

线粒体苹果酸两种不同晶型的结构研究 脱氢酶的测定通过X射线衍射分析进行。 为 形式，两个重原子衍生物已被确定。 在一个例子中， 现在可以关联重原子位置的相对y坐标 通过使用双导数和在低的相位细化的最后阶段， 决议将在下一个赠款期间进行。 第二 晶体形式，重原子位置将使用帕特森方法进行研究。 核磁共振研究的脂质结构域内的可溶性脂蛋白，卵黄脂磷蛋白将 完成。 其余的NMR研究，与Seeling合作， 位于瑞士巴塞尔的Biozentrum将分析31 P弛豫 倍的磷酸丝氨酸和磷脂组分。 松弛时间， T1，将与从结晶脂蛋白中获得的类似数据进行比较。 和其他脂质：蛋白质系统。 与测量数据的比较， 膜蛋白系统，应该有可能了解动态脂质 组织在微域中含有少至30个磷脂分子。 还将尝试测试甘油三酯的交换， 这个脂蛋白系统。 磷脂微区的NMR研究 表明中性脂质的作用可能是形成疏水蛋白 壁的脂质结构域，以前分配给磷脂的一个因素。 这样的 疏水区然后可以用作插入疏水区的边界。 双层样磷脂微区。 如果可以交换2H 标记的甘油三酯进入卵黄脂磷蛋白的脂质结构域，NMR方法将 用于研究脂蛋白中它们的物理性质。

Structural studies of two different crystal forms of mitochondrial malate dehydrogenase are being carried out by x-ray diffraction analysis. For both forms, two heavy atom derivatives have been identified. In one instance, it has now been possible to correlate the relative y-coordinate of the heavy atom sites by using a double derivative and the final stages of phase refinement at low resolution will be carried out during the next grant period. For the second crystal form, heavy atom locations will be studied using Patterson methods. NMR studies of the lipid domain within a soluble lipoprotein, lipovitellin will be completed. The remaining NMR studies, in collaboration with Seeling at the Biozentrum in Basel, Switzerland, will consist of an analysis of 31P relaxation times of both phosphoserine and phospholipid components. The relaxation times, T1, will be compared with similar data obtained from the crystalline lipoprotein and from other lipid:protein systems. The comparison with data measured from membrane protein systems, should make it possible to understand dynamic lipid organization in micro-domains containing as few as 30 phospholipid molecules. An attempt will also be made to test the exchangeability of triglycerides in this lipoprotein system. The NMR studies of the phospholipid micro-domain suggest that the role of neutral lipid may be in forming the hydrophobic protein wall for the lipid domain, a factor previously assigned to phospholipid. Such a hydrophobic region may then serve as the boundary for insertion of the micro-domain of bilayer-like phospholipid. If it is possible to exchange 2H labelled triglycerides into the lipid domain of lipovitellin, NMR methods would be used to study their physical properties within the lipoprotein.