Pautsch A, Schulz G E
Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität, Albertstrasse 21, Freiburg im Breisgau, D-79104, Germany.
J Mol Biol. 2000 Apr 28;298(2):273-82. doi: 10.1006/jmbi.2000.3671.
The membrane domain of OmpA consists of an eight-stranded all-next-neighbor antiparallel beta-barrel with short turns at the periplasmic barrel end and long flexible loops at the external end. The structure analysis has been extended from medium resolution to 1. 65 A (1 A=0.1 nm), and the molecular model has been refined anisotropically to show oriented mobilities of the structural elements. The improved data allowed us to locate five further detergent molecules and 11 more water molecules. Moreover, the two large non-polar packing contacts have now been defined in detail. The analysis indicates that the beta-barrel constitutes a solid scaffold such that the long external loops need not contribute to stability. These loops are highly mobile and thus cause a major problem during the crystallization process. The beta-barrel was related to those of lipocalins. Two further crystal forms with exceptionally dense packing arrangements were established at medium resolution.
外膜蛋白A的膜结构域由一个八链全相邻反平行β桶组成，在周质桶端有短转角，在外端有长的柔性环。结构分析已从中等分辨率扩展到1.65埃（1埃 = 0.1纳米），并且分子模型已进行各向异性优化，以显示结构元件的定向移动性。改进后的数据使我们能够定位另外五个去污剂分子和11个更多的水分子。此外，现在已经详细定义了两个大的非极性堆积接触。分析表明，β桶构成了一个坚实的支架，使得长的外环无需对稳定性有贡献。这些环具有高度的移动性，因此在结晶过程中造成了一个主要问题。β桶与脂质运载蛋白的β桶相关。在中等分辨率下建立了另外两种具有异常紧密堆积排列的晶体形式。
