MACCHESS CONSORTIUM FOR XRAY DETECTORS IN MACROMOLECULAR CRYSTALLOGRAPHY

FHIT基因座上的基因缺失是最常见的， 肺癌和其他几种常见疾病中已知的最早基因变化 人类癌症。FHIT蛋白裂解二核苷酸ApppA 底物，变成AMP加ADP，但我们已经证明了 裂解ApppA的酶与肿瘤抑制因子无关 功能。相反，生化和遗传证据表明，FHIT 作为酶-底物复合体的肿瘤抑制信号。至 定义FHIT蛋白信号的结构基础，我们 将非水解性ApppA类似物与野生型FHIT和 带有突变的FHIT蛋白，该蛋白在ApppA水解过程中存在缺陷。AS 这些晶体是六角形的针形，~270单元格长度、数据 需要在同步加速器源上进行收集。水晶 FHIT底物模拟络合物的结构揭示了一种新的模式 与受调控的蛋白质相似的蛋白质调控 核苷酸结合和受蛋白质调控的蛋白质 磷酸化。正如已经在GTP酶中看到的，GTP酶的结构 底物复合体与产物复合体有很大不同。 然而，与GTP酶不同的是，GTP酶的蛋白质部分 复杂性在很大程度上没有变化。相反，FHIT提供了两个ApppA类似物 在蛋白质的“顶部”表面，取代了深的，正的 带电凹槽。事实上，FHIT-ApppA复合体是“磷酸化的” 六种表面磷酸盐。因此，晶体结构分析表明 FHIT底物复合体是FHIT的活性信号形式。 4.C.布伦纳，H.C.佩斯，P.N.加里森，A.K.罗宾逊，A.R.斯勒，X. 首页--期刊主要分类--期刊细介绍--期刊题录与文摘--期刊详细文摘内容 模拟活性的络合物的提纯和结晶 脆性组氨酸三联体蛋白的状态“，蛋白质工程，V. 10，pp.1461-1463(1997)。H.C.佩斯，P.N.加里森，A.K.罗宾逊， 首页--期刊主要分类--期刊细介绍--期刊题录与文摘--期刊详细文摘内容 C.M.Croce，K.Huebner和C.Brenner，《遗传、生化和 底物模拟络合物的结晶学定义 脆性组氨酸三联体蛋白作为FHIT的活性信号形式， 程序娜塔莉。阿卡德。《科学》，第95卷，第页。5484-5489(1998)。

Genetic deletions at the FHIT locus are the most frequent and the earliest known genetic change in lung cancer and several other common human cancers. The Fhit protein cleaves ApppA, a dinucleotide substrate, into AMP plus ADP, but we have shown that the ability of the enzyme to cleave ApppA does not correlate with tumor suppressor function. Rather, biochemical and genetic evidence indicate that Fhit signals for tumor suppression as an enzyme-substrate complex. To define the structural basis of signaling by Fhit protein, we co-crystallized a nonhydrolyzable ApppA analog with wild-type Fhit and with a mutant Fhit protein that has a defect in ApppA hydrolysis. As these crystals were hexagonal needles with a ~270
cell length, data collection at a synchrotron source was required. The crystal structures of Fhit-substrate analog complexes revealed a novel mode of protein regulation which bears similarities with proteins regulated by nucleotide-binding and with proteins regulated by protein phosphorylation. As has been seen for GTPases, the structure of the substrate complex is quite different from the product complex. However, unlike the case of GTPases, the protein portion of the complex is largely unchanged. Rather, Fhit presents two ApppA analogs on the "top" surface of the protein in place of a deep, positively charged groove. Fhit-ApppA complexes are, in fact, "phosphorylated" by six surface phosphates. Thus, crystal structure analysis suggests that Fhit-substrate complexes are the active, signaling form of Fhit. 4. C. Brenner, H.C. Pace, P.N. Garrison, A.K. Robinson, A. R sler, X. Liu, G.M. Blackburn, C.M. Croce, K. Huebner & L.D. Barnes, "Purification and Crystallization of Complexes Modeling the Active State of the Fragile Histidine Triad Protein," Protein Engineering, v. 10, pp. 1461-1463 (1997). H.C. Pace, P.N. Garrison, A.K. Robinson, L.D. Barnes, A. Draganescu, A. R sler, G.M. Blackburn, Z. Siprashvili, C.M. Croce, K. Huebner & C. Brenner, "Genetic, Biochemical and Crystallographic Definition of a Substrate Analog Complex with the Fragile Histidine Triad Protein as the Active Signaling Form of Fhit," Proc. Natl. Acad. Sci., v. 95, pp. 5484-5489 (1998).