Protein Structure

在过去几年里，我们的工作集中在四个不同的领域。蛋白水解酶的结晶学研究自该科成立以来，对蛋白水解酶的结晶学研究一直是一个重要的研究领域。我们在天冬氨酸蛋白酶的结构-功能关系的研究中尤其活跃，包括临床上重要的逆转录病毒酶。我们对HIV蛋白水解酶的研究虽然不再是活跃研究的主要目标，但仍在进行中，并集中在耐药变异体及其与抑制剂的复合体的研究上。我们已经研究了来自其他几个来源的逆转录病毒蛋白酶，如FIV，RSV和HTLV，最近解决了后者的结构。蟑螂变应原Bla-g-2是一种失活的天冬氨酸蛋白水解酶，我们将其结构与特异性抗体结合。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，这个家族最初是基于本实验室解决的晶体结构而确定的，并在许多不同的生物体中发现。我们还研究了细菌ATP依赖的蛋白水解酶Lon，发现它的蛋白水解区有一个独特的折叠，从而建立了一个具有Ser-Lys催化二聚体的新的蛋白水解酶家族。我们已经解决了由E.Coli和Archaeoglobus fulgidus编码的A和B型Lon蛋白酶的蛋白水解域的结构，以及E.ColiLong的N端和Alpha结构域。具有抗病毒活性的凝集素我们已经参与了几种具有抗病毒活性的凝集素的研究，其中一些目前正在进行临床前试验，作为潜在的预防HIV感染的药物。我们已经解决了Griffithsin的结构，作为游离蛋白质，并与一些单糖和双糖络合，解释了它与富含甘露糖的支链碳水化合物紧密结合的结构基础。我们还结晶了另一种凝集素--镰刀菌素。参与核糖体生物发生和肿瘤抑制的蛋白质Rio1和RIO2是两个相关的丝氨酸蛋白激酶，它们参与将20S Pre-RNA加工成18S核糖体RNA。本课题组对它们的晶体结构进行了解析，确定它们属于一个新的具有截短底物结合区的激酶家族，尽管它们同时具有自磷酸化和反式磷酸化的能力。我们已经确定了这两个基因的自磷酸化位点。我们目前正在研究它们的催化性能和潜在的生物学作用。我们还解决了Pdcd4的C-末端MA3结构域的结构，解释了肿瘤抑制因子是如何抑制翻译启动的。细胞因子和细胞因子受体我们研究组一直在研究几种细胞因子的晶体结构，并在制备它们的受体复合体方面取得了进展。我们已经提纯和结晶了IL-10与其特异性受体的复合物，并正在研究其他几种与IL-10相关的细胞因子的复合物，如IL-19、IL-20和IL-22。

In the past several years, our work has concentrated in four 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, having recently solved the structure of the latter enzyme. Cockroach allergen Bla g 2 was shown to be an inactive aspartic protease and we solved its structure in a complex with specific antibody. 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. We have solved the structures of the proteolytic domain of A and B type Lon proteases, encoded by E. coli and Archaeoglobus fulgidus, as well as the N-terminal and alpha domains of E. coli Lon.Lectins with antiviral activityWe have been involved in studies of several lectins with antiviral activities, some of them currently being in pre-clinical trials as potential drugs preventing HIV infection. We have solved the structure of griffithsin, as free protein and complexed with a number of mono- and disaccharides, explaining the structural basis for its tight binding to branched mannose-rich carbohydrates. We have also crystallized another lectin, scytovirin. Proteins involved in ribosome biogenesis and tumor suppressionTwo 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 have established the sites of autophosphorylation for both of them. We are currently investigating their catalytic properties and a potential biological role. We have also solved the structure of the C-terminal MA3 domain of Pdcd4, explaining how that tumor suppressor factor inhibits translation initiation. 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 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.