TELOMERE END BINDING PROTEIN OF O NOVA COMPLEXED W/ SSDNA/POLIOVIRUS POLYMERASE

端粒是核蛋白复合物， 真核生物的染色体。 我们已经解决了晶体结构， 适度的分辨率，对于由0. nova端粒末端结合蛋白和单链DNA。 其中一 复合物，形成为α亚基、β亚基和β亚基的三元复合物。 亚基和12个ntd的ssDNA代表了真正的3'末端 端粒（2.8A，Horvath等，1998年）。 第二个复合体是 由单独的α亚基和ssDNA（2.8A，Peersen 未公开）和第三个作为α亚基N末端组装， DNA结合结构域和ssDNA（3.2A，Classen，未发表）。 在一起， 这些复合物突出了在形成过程中可能形成的各种相互作用， 天然端粒复合体的组装。 此外，核苷酸 α：β：ssDNA复合物的取代变体已经被 结晶提供了一个机会来测试的作用， 相互作用在单链DNA的序列特异性识别中起作用， 端粒复合体 我们的目标是收集更高分辨率的数据， 这些端粒复合体。 脊髓灰质炎病毒RNA依赖性RNA聚合酶： 小正链RNA病毒，如鼻病毒、甲型肝炎病毒和 脊髓灰质炎是重要的病原体。 在生命周期的中心， 这些病毒是RNA依赖的RNA聚合酶。 我们已经解决了 脊髓灰质炎病毒RNA聚合酶的结构，分辨率为2.6 A （汉森，1997年），第一个也是唯一的结构，在这一类的 RNA到RNA聚合酶，包括超过4，100种已知或推定的 成员 晶体最初是在高盐条件下制备的 (2M CaCl）。 最近已经制备了一种替代的晶体形式 将这些高盐晶体转化为低盐晶体。 备用 形式表现出单位单元c轴的加倍和 3倍螺旋轴的旋向性。 此外，构象 在聚合酶的一个区域观察到开关， 与这种酶的功能有关。 两种晶体形式都揭示了 我们认为这种广泛的聚合酶-聚合酶相互作用 对于RNA结合和复制活性重要。 我们的目标是 收集高盐和低盐形式的更高分辨率数据， 脊髓灰质炎病毒聚合酶 在BioCARS Station 14上收集数据 BM-C

Telomeres are the nucleoprotein complexes that make up the ends of chromosomes in eukaryotes. We have solved the crystal structure, at modest resolution, for three different complexes formed by the 0. nova telomere end binding protein and single stand DNA. One of these complexes, formed as a ternary complex of the alpha subunit, the beta subunit, and a 12-ntd ssDNA, represents the authentic 3' terminus of the telomere (2.8 A, Horvath et al., 1998). A second complex is formed by the alpha subunit alone and ssDNA (2.8 A, Peersen unpublished) and a third is assembled as the alpha subunit N terminal, DNA-binding domain and ssDNA (3.2 A, Classen, unpublished). Together, these complexes highlight the varied interactions that may form during assembly of the natural telomere complex. Additionally, nucleotide substitution variants of the alpha:beta:ssDNA complex have been crystallized providing an opportunity to test the role that certain interactions play in sequence specific recognition of ssDNA within the telomere complex. Our aim is to collect higher resolution data for these telomere complexes. Poliovirus RNA dependent RNA polymerase: Small positive strand RNA viruses such as rhinovirus, hepatitis A, and polio are important pathogens. At the center of the life cycle for these viruses is an RNA-dependent RNA polymerase. We have solved the structure of the poliovirus RNA polymerase to 2.6 A resolution (Hansen, 1997), the first and only structure in this class of RNA-to-RNA polymerases which comprises over 4, 100 known or putative members. Crystals were originally prepared under high salt conditions (2M CaCl). More recently an alternate crystal form has been prepared by transferring these high-salt crystals into low salt. The alternate form exhibits a doubling of the unit cell c axis and a switch in the handedness of the 3 fold screw axis. Additionally, a conformational switch is observed in one region of the polymerase which likely relates to the function of this enzyme. Both crystal forms reveal extensive polymerase-polymerase interactions which we believe are important for RN A binding and replication activity. Our aim is to collect higher resolution data for both the high and low salt forms of the poliovirus polymerase. Data was collected on BioCARS Station 14 BM-C.