Luginbühl P, Ottiger M, Mronga S, Wüthrich K
Institut für Molekularbiologie und Biophysik, Eidgenössische Technische Hochschule-Hönggerberg, Zürich, Switzerland.
Protein Sci. 1994 Sep;3(9):1537-46. doi: 10.1002/pro.5560030919.
The NMR structures of the homologous pheromones Er-1, Er-10, and Er-2 from the ciliated protozoan Euplotes raikovi are compared. For all 3 proteins the molecular architecture is made up of an antiparallel 3-helix bundle. The preservation of the core part of the structure is directly manifested by similar patterns of slowed backbone amide proton exchange rates, hydrogen bond formation, and relative solvent accessibility. To align the 6 half-cystine residues in the individual sequences within the preserved 3-dimensional core structure, several deletions and insertions had to be introduced that differ from those previously proposed on the basis of the primary structures. Of special interest is a deletion in the second helix of Er-2, which is accommodated by a transition from an alpha-helix in Er-1 and Er-10 to a 3(10)-helix in Er-2. The most significant structural differences are located in the C-terminal part of the proteins, which may have an important role in specific receptor recognition.
对来自纤毛原生动物雷氏游仆虫的同源信息素Er-1、Er-10和Er-2的核磁共振结构进行了比较。对于所有这三种蛋白质，分子结构均由一个反平行的三螺旋束组成。结构核心部分的保留直接表现为相似的主链酰胺质子交换速率减缓模式、氢键形成以及相对溶剂可及性。为了在保留的三维核心结构内的各个序列中对齐6个半胱氨酸残基，必须引入一些缺失和插入，这些与之前基于一级结构提出的不同。特别有趣的是Er-2第二个螺旋中的一个缺失，它通过从Er-1和Er-10中的α螺旋转变为Er-2中的3(10)螺旋来适应。最显著的结构差异位于蛋白质的C末端部分，这可能在特异性受体识别中起重要作用。
