Green Todd J, Luo Ming
Department of Microbiology, School of Medicine, University of Alabama at Birmingham, 1025 18th Street South, Birmingham, AL 35294, USA.
Acta Crystallogr D Biol Crystallogr. 2006 May;62(Pt 5):498-504. doi: 10.1107/S0907444906006809. Epub 2006 Apr 19.
Vesicular stomatitis virus (VSV) is a non-segmented negative-stranded RNA virus. The nucleocapsid (N) protein of VSV is found tightly associated with the viral genomic RNA and this complex serves as the template for transcription and replication. A method for the soluble expression of the N protein in Escherichia coli has previously been reported. An N protein-RNA oligomer was isolated from this system, the stoichiometry of which was determined to be ten molecules of the N protein bound to approximately 90 nucleotides of RNA. Here, the crystallization of this protein-nucleic acid complex is presented. The crystals belong to space group P2(1)2(1)2, with unit-cell parameters a = 165.65, b = 235.35, c = 75.71 A and a diffraction limit of 6 A. Self-rotation function analysis has shown the oligomer to have tenfold rotational symmetry. In a search to identify heavy-atom derivatives, uranyl acetate was discovered to stabilize the crystals, giving them an increase in diffraction limits to beyond 2.9 A. Based on the internal symmetry of the oligomer, the size of the oligomer determined previously by negative-stained electron microscopy, the space-group symmetry and packing considerations, the packing arrangement in the crystal has been determined.
水泡性口炎病毒（VSV）是一种不分节段的负链RNA病毒。VSV的核衣壳（N）蛋白与病毒基因组RNA紧密结合，这种复合物作为转录和复制的模板。此前已有报道一种在大肠杆菌中可溶性表达N蛋白的方法。从该系统中分离出一种N蛋白-RNA寡聚物，其化学计量比为十个N蛋白分子与大约90个核苷酸的RNA结合。在此，展示了这种蛋白质-核酸复合物的晶体结构。晶体属于空间群P2(1)2(1)2，晶胞参数a = 165.65，b = 235.35，c = 75.71 Å，衍射极限为6 Å。自旋转函数分析表明该寡聚物具有十重旋转对称性。在寻找重原子衍生物的过程中，发现醋酸铀酰可稳定晶体，使其衍射极限提高到2.9 Å以上。基于寡聚物的内部对称性、先前通过负染电子显微镜确定的寡聚物大小、空间群对称性和堆积考虑因素，已确定了晶体中的堆积排列。
