Protein Structure

研究我们主要通过高分辨率X射线衍射技术研究蛋白质结构和功能之间的关系。在过去几年中，我们的工作集中在三个不同的领域。蛋白酶的晶体学研究蛋白酶的晶体学研究是本部门自成立以来的一个重要研究领域。我们一直特别积极地研究天冬氨酸蛋白酶的结构-功能关系，包括临床上重要的逆转录病毒酶。我们对HIV蛋白酶的研究虽然不再是积极研究的主要目标，但仍在进行中，并集中于耐药变体及其与抑制剂的复合物的研究。我们已经研究了其他几种来源的逆转录病毒蛋白酶，如FIV、RSV和HTLV。蛋白酶A与其特异性蛋白抑制剂的复合物已将这种酶确立为其自身抑制的伴侣，并首次提供了天冬氨酸蛋白酶螺旋抑制剂的一瞥。蟑螂变应原Blag 2是一种无活性的天冬氨酸蛋白酶.我们已经建立了一个广泛的研究丝氨酸羧基肽酶（sedolisins）的计划，该家族首先基于本实验室解决的晶体结构进行表征，并在许多不同的生物体中发现。我们还研究了细菌ATP依赖性蛋白酶Lon，发现其蛋白水解结构域具有独特的折叠，从而建立了一个新的具有Ser-Lys催化二联体的蛋白酶家族。细胞因子和细胞因子受体本科一直在研究几种细胞因子的晶体结构，并在制备其受体复合物方面取得了进展。我们已经确定，螺旋细胞因子，白细胞介素-10（IL-10），是一个结构域交换的二聚体，其中每个紧凑的一半是由两个相同的分子的片段。EB病毒基因组中编码的相关细胞因子的结构现在已经确定，这提供了病毒用于控制宿主免疫系统的试剂的分子结构的第一个一瞥。我们还解决了IL-19的晶体结构。我们已经纯化并结晶了IL-10与其特异性受体的复合物，并且正在研究与IL-10相关的几种其他细胞因子的复合物，例如IL-19、IL-20和IL-22。参与核糖体生物发生和RNA干扰的蛋白质两种相关的丝氨酸蛋白激酶Rio 1和Rio 2参与将20 S前体RNA加工成18 S核糖体RNA。我们的部门解决了它们的晶体结构，确定它们属于一个新的激酶家族，具有截短的底物结合区，尽管它们能够自我磷酸化和反式磷酸化。我们目前正在研究它们的催化特性和潜在的生物学作用。我们还在研究Dicer的结构，Dicer是RNA干扰途径中的一种关键酶。

Research We are investigating the relationship between protein structure and function, mainly by the technique of high-resolution X-ray diffraction. In the past several years, our work has concentrated in three distinct areas. Crystallographic studies of proteases Crystallographic studies of proteases have been an important area of research of this Section since its establishment. We have been particularly active in the investigation of structure-function relationship in aspartic proteases, including clinically important retroviral enzymes. Our studies of HIV protease, although no longer a major target of active research, are still ongoing and concentrate on the investigation of drug-resistant variants and their complexes with inhibitors. We have investigated retroviral proteases from several other sources such as FIV, RSV, and HTLV. A complex of proteinase A with its specific protein inhibitor has established this enzyme as a chaperone for its own inhibition and provided the first glimpse of a helical inhibitor of aspartic proteases. Cockroach allergen Bla g 2 was shown to be an inactive aspartic protease. We have established an extensive program of investigating serine-carboxyl peptidases (sedolisins), a family that was first characterized based on crystal structures solved in this laboratory and that is found in many different organisms. We are also investigating a bacterial ATP-dependent protease Lon, finding that is proteolytic domain has a unique fold and thus establishes a new family of proteases with a Ser-Lys catalytic dyad. Cytokines and cytokine receptors Our Section has been investigating the crystal structures of several cytokines and has made progress in preparing their receptor complexes. We have established that a helical cytokine, interleukin-10 (IL-10), is a domain-swapped dimer in which each compact half is composed of fragments of two identical molecules. The structure of a related cytokine encoded in the genome of Epstein-Barr virus has now been determined, providing the first glimpse of the molecular architecture of an agent used by the virus to control the host's immune system. We also solved the crystal structure of IL-19. We have purified and crystallized complexes of IL-10 with its specific receptor and are studying complexes of several other cytokines related to IL-10, such as IL-19, IL-20, and IL-22. Proteins involved in ribosome biogenesis and RNA interference Two related serine protein kinases, Rio1 and Rio2, are involved in processing 20S pre-RNA to 18S ribosomal RNA. Their crystal structures, solved by our Section, established that they belong to a novel family of kinases with a truncated substrate-binding region, although they are capable of both self- and trans-phosphorylation. We are currently investigating their catalytic properties and a potential biological role. We are also working on structural studies of Dicer, an enzyme crucial in the RNA interference pathway.