权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Three-dimensional structure of tandem repeats within RNA polymerase II, prion, and LEA proteins

RNA 聚合酶 II、朊病毒和 LEA 蛋白内串联重复序列的三维结构

基本信息

批准号：
10680637
负责人：
MATSUSHIMA Norio
金额：
$ 1.86万
依托单位：
Sapporo Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10680637/
关键词：
Prion RNA polymrase II Tandem repeats NMR β-turn RNAポリメーラーゼ RNAポリメラーゼ RNAポロメラーゼII LEA CD

项目摘要

The "prion hypothesis" holds that an aberrant conformation of a normal cellular prion protein is the essential, perhaps sole, component of infection agent responsible for several fatal neurodegenerative diseases, including the human genetic disease CJB.The N-terminal region of the prion protein contains five tandem repeats with the consensus sequence of PHGGGWGQ.NMR studies were performed in water for four peptides including C^1R^2Q^3P^4H^5G^6G^7S^8W^9G^<10>Q^<11>R^<12>D^<13>C^<14> (L1). The patterns of the C_αH chemical shift difference of these four peptide mimetics were very similar to those observed for the tandem repeats of human prion protein reported by other researchers. The medium-range NOE connectivities were found between the C_βH of the H5 and the proton of the W9 side chain for L1. These observations indicate that histidine (i) is in close proximity to tryptophan (i+4). Structure calculations for L1 showed that HGG (G/S) W and (G/S) WGQ adopt a loop conformation and a β-turn, respectively.The carboxyl terminal domain (CTD) of RNA polymerase II, which is rich in phosphorylation sites, contains 17-52 tandem repeats with the consensus sequence of the heptapeptide, YSPTSPS.The repeat unit of the heptapeptide has two SPXX motifs showing potential β-turns, SPTS and SPSY.NMR studies were performed in water at pH4.0 for two cyclic peptides containing one and two repeat units, cyclo-[C^1R^2D^3Y^4S^5P^6T^7S^8P^9S^<10>Y^<11>S^<12>R^<13>D^<14>C^<15>] and cyclo-[C^1R^2D^3Y^4S^5P^6T^7S^8P^9S^<10>Y^<11>S^<12>P^<13>T^<14>S^<15>P^<16>N^<17>Y^<18>S^<19>R^<20>D^<21>C^<22>]. Conformations consistent with NMR parameters including NOE distances were obtained through molecular dynamics and energy minimization methods. These calculations yielded two stable conformers for the SPTS segment. One of the two corresponds to a type I β-turn.

“朊病毒假说”认为，正常细胞朊病毒蛋白的异常构象是导致几种致命神经退行性疾病的感染因子的基本成分，朊病毒蛋白的N端含有5个串联重复序列，共有序列为PHGGGWGQ。5G ^6G ^7S ^8W ^9G ^<10>Q^<11>R^<12>D^<13>C^<14>（L1）。这四种肽模拟物的C_αH化学位移差异模式与其他研究者报道的人朊蛋白串联重复序列的C_αH化学位移差异模式非常相似。H5的C_βH与L1的W 9侧链质子之间存在中程NOE连接性。这些观察结果表明，组氨酸（i）与色氨酸（i+4）非常接近。对L1的结构计算表明，HGG（G/S）W和（G/S）WGQ分别为环状构象和β-转角，RNA聚合酶II的羧基末端结构域（CTD）含有17-52个串联重复单元，与七肽YSPTSPS的共有序列相同，具有丰富的磷酸化位点，七肽的重复单元有两个SPXX基序，显示潜在的β-转角，在pH4.0的水中对含有一个和两个重复单元的两种环肽进行NMR研究，所述环肽为环-[<10>C^1R^2D^3Y^4S^5P^6T^7S^8P^9S^Y^S^R^D^C <11><12><13><14>^<15>]和环-[<10>C^1R^2D^3Y^4S^5P^6T^7S^8P^9S^Y^S^P^T^S^P^N^Y^S^R^D^C <11><12><13><14><15><16><17><18><19><20><21>^<22>]。通过分子动力学和能量最小化方法得到与NMR参数（包括NOE距离）一致的构象。这些计算产生了两个稳定的构象的SPTS段。两者之一对应于I型β转弯。