检索结果-内蒙古大学图书馆

solution structure OF THE NA+ FORM OF THE DIMERIC GUANINE QUADRUPLEX [D(G(3)T(4)G(3))](2)

EUROPEAN JOURNAL OF BIOCHEMISTRY 1995年第2期233卷 631-643页

作者： KENIRY, MA STRAHAN, GD OWEN, EA SHAFER, RH UNIV CALIF SAN FRANCISCO SCH PHARM DEPT PHARMACEUT CHEM SAN FRANCISCO CA 94143 USA AUSTRALIAN NATL UNIV RES SCH CHEM CANBERRA ACT AUSTRALIA

The solution structure of the DNA quadruplex formed by the association of two strands of the DNA oligonucleotide, d(G(3)T(4)G(3)), in NaCl solution has been determined by H-1 two-dimensional NMR techniques, full relaxation matrix calculations and restrained molecular dynamics. The refined structure incorporates the sequences 5'-G1(S)G2(A)G3(A)T4(A)T5(A)T6(A)T7(A)G8(S)G9(A)G10(A)-3' and 5'-G11(S)G12(A)G13(A)T14(A)T15(A). T16(A)T17(A)G18(S)G19(S)G20(A)-3' (where S and A denote syn and anti, respectively) in a three-quartet, diagonal-looped structure that we [Strahan, G. D., Shafer, R. H. & Keniry, M. A. (1994) Nucleic Acids Res. 22, 5447-5455] and others [Smith, F. W., Lau, F. W. & Feigon, J. (1994) Proc. Natl Acad. Sci. USA 91, 10546-10550] have described. The loop structure is compact and incorporates many of the features found in duplex hairpin loops including base stacking, intraloop hydrogen bonding and extensive van der Waals' interactions. The first and third loop thymines stack over the outermost G-quartet and are also associated by hydrogen bonding. The second and the fourth loop thymines fold inwards in order to enhance van der Waals' interactions. The unexpected sequential syn-syn deoxyguanosines in the quadruplex stem appear to be a direct consequence of the way DNA oligonucleotides fold and the subsequent search for the most stable loop structure. The implications of loop sequence and length on the structure of quadruplexes are discussed.

关键词： G-QUARTET QUADRUPLEX solution structure TELOMERE 2-DIMENSIONAL NMR

来源：评论

学校读者我要写书评

暂无评论

solution structure of α-conotoxin MI determined by ¹H-NMR spectroscopy and molecular dynamics simulation with the explicit solvent water

引用

BIOCHIMICA ET BIOPHYSICA ACTA-PROTEIN structure AND MOLECULAR ENZYMOLOGY 1997年第2期1343卷 327-334页

作者： Gouda, H Yamazaki, K Hasegawa, J Kobayashi, Y Nishiuchi, Y Sakakibara, S Hirono, S Kitasato Univ Sch Pharmaceut Sci Minato Ku Tokyo 108 Japan Daiichi Pharmaceut Co Ltd Inst Dev Res Edogawa Ku Tokyo 134 Japan Osaka Univ Fac Pharmaceut Sci Osaka 565 Japan Peptide Inst Inc Prot Res Fdn Osaka 562 Japan

The conformation of alpha-conotoxin MI, a potent antagonist of the nicotinic acetylcholine receptor, has been investigated in aqueous solution. Two-dimensional NMR experiments and simulated annealing calculations provide the overall topology of alpha-conotoxin MI;then molecular dynamics simulation with the explicit solvent water was followed in order to obtain a more reliable solution structure. The resulting conformation indicates the presence of a 3(I0) helix and a type I beta-turn for residues Pro6-Cys8 and Gly9-Try12, respectively, and shows a significant structural similarity to that of alpha-conotoxin GI, which has biological activity similar to that of MI. The present study provides a molecular basis for the alpha-conotoxin-receptor interaction. (C) 1997 Elsevier Science B.V.

关键词： solution structure neurotoxin 2D NMR molecular dynamics simulation acetylcholine receptor (Conus magus)

来源：评论

学校读者我要写书评

暂无评论

solution structure of Azidoalcohols Studied by IR Spectroscopy and Quantum Chemistry

引用

JOURNAL OF APPLIED SPECTROSCOPY 2014年第1期81卷 23-30页

作者： Karpov, S. V. Lodygina, V. P. Malkov, G. V. Russian Acad Sci Inst Problems Chem Phys Chernogolovka 142432 Moscow Region Russia

Features of the association of azidoalcohols in CH2Cl2 were studied by IR spectroscopy using 1,3-diazidopropan-2-ol and 1-azidoethan-2-ol as examples. It was established that the investigated compounds could exist as two types of [OHaEuro broken vertical bar N-3] associates. In the fi rst instance, the OH group was affected by strong intermolecular interactions like in common alcohols;in the second, the interactions were much weaker. Density functional theory and quantum theory of atoms-in-molecules were used to determine the structures of such associates and the energy parameters of the observed intermolecular interactions. Also, the experimental and calculated frequencies of OH stretching vibrations were correlated.

关键词： 1,3-diazidopropan-2-ol 1-azidoethan-2-ol azidoalcohol CH2Cl2 solution structure non-covalent interactions hydrogen bond IR spectroscopy quantum theory of atoms-in-molecules density functional theory

来源：评论

学校读者我要写书评

暂无评论

solution structure of a Nedd4 WW domain-ENaC peptide complex

引用

NATURE STRUCTURAL BIOLOGY 2001年第5期8卷 407-412页

作者： Kanelis, V Rotin, D Forman-Kay, JD Hosp Sick Children Programme Struct Biol & Biochem Toronto ON M5G 1X8 Canada Hosp Sick Children Programme Cell Biol Toronto ON M5G 1X8 Canada Univ Toronto Dept Biochem Toronto ON M5S 1A8 Canada

Nedd4 is a ubiquitin protein ligase composed of a C2 domain, three (or four) WW domains and a ubiquitin ligase Hect domain. Nedd4 was demonstrated to bind the epithelial sodium channel (alpha beta gamma ENaC), by association of its WW domains with PY motifs (XPPXY) present in each ENaC subunit, and to regulate the cell surface stability of the channel. The PY motif of beta ENaC is deleted or mutated in Liddle syndrome. a hereditary form of hypertension caused by elevated ENaC activity. Here we report the solution structure of the third WW domain of Nedd4 complexed to the PY moth-containing region of beta ENaC (TLPIPGTPPPNYDSL, referred to as beta P2). A polyproline type II helical conformation is adopted by the PPPN sequence. Unexpectedly, the C-terminal sequence YDSL forms a helical turn and both the tyrosine and the C-terminal leucine contact the WW domain. This is unlike other proline-rich peptides complexed to WW domains, which bind in an extended conformation and lack molecular interactions with residues C-terminal to the tyrosine or the structurally equivalent residue in non-PY motif WW domain targets. The Nedd4 WW domain-ENaC beta P2 peptide structure expands our understanding of the mechanisms involved in WW domain-ligand recognition and the molecular basis of Liddle syndrome.

关键词： Helical Liddle Syndrome WW domain NEDD4 gene Tyrosine surface stability P2 peptide ubiquitin protein ligase solution structure CARBON YARN Carboxy-Terminal Amino Acid

来源：评论

学校读者我要写书评

暂无评论

solution structure of the human parvulin-like peptidyl prolyl cis/trans isomerase, hPar14

引用

JOURNAL OF MOLECULAR BIOLOGY 2001年第4期305卷 917-926页

作者： Terada, T Shirouzu, M Fukumori, Y Fujimori, F Ito, Y Kigawa, T Yokoyama, S Uchida, T RIKEN Yokohama Inst Genom Sci Ctr Yokohama Kanagawa 2300045 Japan Univ Tokyo Grad Sch Sci Dept Biophys & Biochem Bunkyo Ku Tokyo 1130033 Japan RIKEN Harima Inst SPring 8 Sayo Hyogo 6795148 Japan Sci Univ Tokyo Dept Biol Sci & Technol Lab Genome Biol Noda Chiba 2788510 Japan Tohoku Univ Inst Dev Aging & Canc Aoba Ku Sendai Miyagi 9808575 Japan

The hPar14 protein is a peptidyl prolyl cis/trans isomerase and is a human parvulin homologue. The hPar14 protein shows about 30% sequence identity with the other human parvulin homologue, hPin1. Here, the solution structure of hPar14 was determined by nuclear magnetic resonance spectroscopy. The N-terminal 35 residues preceding the peptidyl prolyl isomerase domain of hPar14 are unstructured, whereas hPin1 possesses the WW domain at its N terminus. The fold of residues 36-131 of hPar14, which comprises a four-stranded beta -sheet and three alpha -helices, is superimposable onto that of the peptidyl prolyl isomerase domain of hPin1. To investigate the interaction of hPar14 with a substrate, the backbone chemical-shift changes of hPar14 were monitored during titration with a tetra peptide. Met90, Val91, and Phe94 around the N terminus of alpha3 showed large chemical-shift changes. These residues form a hydrophobic patch on the molecular surface of hPar14. Two of these residues are conserved and have been shown to interact with the proline residue of the substrate in hPin1. On the other hand, hPar14 lacks the hPin1 positively charged residues (Lys63, Arg68, and Arg69), which determine the substrate specificity of hPinl by interacting with phosphorylated Ser or Thr preceding the substrate Pro, and exhibits a different structure in the corresponding region. Therefore, the mechanism determining the substrate specificity seems to be different between hPar14 and hPin1. (C) 2001 Academic Press.

关键词： hPar14 peptidyl prolyl cis/trans isomerase hPin1 nuclear magnetic resonance solution structure

来源：评论

学校读者我要写书评

暂无评论

solution structure of cyanoferricytochrome c:: ligand-controlled conformational flexibility and electronic structure of the heme moiety

引用

JOURNAL OF BIOLOGICAL INORGANIC CHEMISTRY 2002年第4-5期7卷 539-547页

作者： Yao, Y Qian, CM Ye, KQ Wang, JF Bai, ZP Tang, WX Nanjing Univ State Key Lab Coordinat Chem Nanjing 210093 Peoples R China Acad Sinica Inst Biophys Natl Lab Biomacromol Beijing 100101 Peoples R China

The solution structure of cyanoferricytochrome c has been determined using NMR spectroscopy. As a result of including additional constraints derived from pseudocontact shifts, a high-resolution NMR structure was obtained with high accuracy. In order to study the conformational transition between the native protein and its ligand adducts, the present structure was compared with the solution structures of the wild-type cytochrome c and the imidazole-cytochrome c complex. Like the solution structure of imidazole-cytochrome c, the heme crevice is widened by the swinging out of residues 77-85 and a noticeable shift of the 50s helix. However, unlike imidazole, cyanide exerts less significant perturbation on the conformation of the heme cavity, which is revealed by a more compact residue package in the distal pocket. Furthermore, comparison of the solution structure of CN-iso-1Met80Ala cytochrome c with the structure of cyanoferricytochrome c indicated that the binding of cyanide has a different impact on the distal cavity conformation in the two proteins. In addition, the magnetic properties of the present system are discussed and a comprehensive study of the electronic structure of ligand-cytochrome c complexes and the native protein is also described. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://***/10.1007/s00775-001-0334-y.

关键词： cytochrome c cyanide solution structure conformational transition electronic structure

来源：评论

学校读者我要写书评

暂无评论

solution structure of the cryptic mannitol-specific phosphotransferase enzyme IIA CmtB from Escherichia coli

引用

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 2007年第4期362卷 1001-1006页

作者： Yu, Caifang Li, You Xia, Bin Jin, Changwen Peking Univ Beijing Nucl Magnet Resonance Ctr Beijing 100871 Peoples R China Peking Univ Coll Chem & Mol Engn Beijing 100871 Peoples R China Peking Univ Coll Life Sci Beijing 100871 Peoples R China

The bacterial phosphoenolpyruvate-dependent sugar phosphotransferase system (PEP-PTS) is essential in the coupled transportation and phosphorylation of various types of carbohydrates. The CmtAB proteins of Escherichia coli are sequentially similar to the mannitol-specific phosphotransferase MtlA. The CmtB protein corresponds to the phosphotransferase enzyme IIA component. Here we report the solution structure of CmtB from E. coli at high resolution by NMR spectroscopy. The results show that CmtB adopts a globular fold consisting of a central mixed five-strand (beta-sheet flanked by seven helices at both sides. Structural comparison with the IIA domain of MtlA (IIA(Mtl)) reveals high overall similarity, while notable conformational differences at the active site are observed. The active site pocket of CmtB appears to be wider, and the hydrophobic regions around it is larger compared to IIA(Mtl). Further, the essential arginine residue at the active site of IIA(Mtl) is substituted by a serine in CmtB. Instead, the active pocket of CmtB contains another arginine at a distinct position, suggesting different molecular mechanisms for phosphoryl transfer. (C) 2007 Elsevier Inc. All rights reserved.

关键词： CmtB phosphotransferase mannitol NMR solution structure

来源：评论

学校读者我要写书评

暂无评论

solution structure and backbone dynamics of the AF-6 PDZ domain/Bcr peptide complex

引用

PROTEIN SCIENCE 2007年第6期16卷 1053-1062页

作者： Chen, Quan Niu, Xiaogang Xu, Yingqi Wu, Jihui Shi, Yunyu Univ Sci & Technol China Sch Life Sci Hefei 230026 Anhui Peoples R China Univ Sci & Technol China Hefei Natl Lab Phys Sci Microscale Hefei 230026 Anhui Peoples R China

The human AF-6, a scaffold protein between cell membrane-associated proteins and the actin cytoskeleton, plays an important role in special cell-cell junctions and signal transduction. It can be phosphorylated by the protein kinase Bcr, which allows efficient binding of the C terminus of Bcr to the PDZ domain of AF-6 and consequently enhances the binding affinity of AF-6 to Ras. Formation of the AF-6, Bcr, and Ras ternary complex results in down-regulation of the Ras-mediated signal transduction pathway. To better understand the molecular basis for the recognition of the AF-6 PDZ domain and Bcr, we solve the solution structure of the AF-6 PDZ domain complexed with the C-terminal peptide of Bcr and explore the interactions between them in detail. Compared with previously reported structures, the complex exhibits a noncanonical binding mode of PDZ/peptide. Owing to the distinct residues involved in the AF-6 PDZ domain and Bcr peptide interaction, the interaction mode does not adapt to the existing classification rules that have been put forward, based on the ligand or the PDZ domain specificity. Furthermore, the PDZ domain of AF-6 can bind to the C terminus of Bcr efficiently after phosphorylation of AF-6 by the Bcr kinase. The phosphorylation may induce a conformational change of AF-6, which makes the binding surface on the PDZ domain accessible to Bcr for efficient binding. This study not only characterizes the structural details of the AF-6 PDZ/Bcr peptide complex, but also provides a potential target for future drug design and disease therapy.

关键词： PDZ domain AF-6 complex solution structure backbone dynamics

来源：评论

学校读者我要写书评

暂无评论

solution structure, crystal structure, Hirshfeld surface analysis of copper(II) diamide species as an optical chemical sensor

引用

POLYHEDRON 2024年 256卷

作者： Elmagbari, Fatin M. Hammouda, Ahmed N. Soliman, Saied M. EL-Ferjani, Rashd. M. Elagili, Fareedah A. Ben Amer, Younis. O. Jackson, Graham E. Bonomo, Raffaele P. Univ Cape Town Dept Chem ZA-7700 Rondebosch South Africa Univ Benghazi Fac Sci Dept Chem POB 9480 Benghazi Libya Alexandria Univ Fac Sci Dept Chem POB 426 Ibrahima Alexandria 21525 Egypt Univ Catania Dept Chem Sci Viale A Doria 6 I-95125 Catania Italy

Optical chemical sensors are promising tools for the detection of metal ions in various samples. Copper(II) has received significant attention among metal ions due to its toxic nature and widespread applications in various industrial processes. In recent years, several optical chemical sensors have been developed to detect copper(II) with high sensitivity and selectivity. This paper describes the spectrophotometric determination of trace amounts of copper(II) using N1-(2-aminoethyl)-N2-((pyridin-2-yl)methyl)oxalamide (H2(555)NH2) as an optical chemical sensor. The protonation and formation constants of the Cu(II)/(H2(555)NH2) system were determined at 25 degrees C and the ionic strength of 0.15 mol dm- 3 using glass electrode potentiometry. The structures of the different species, present in solution at different pH values, were determined using UV-vis, 1H NMR, and EPR spectroscopic techniques. At pH 5, the [Cu(H2(555)NH2)]2+ species was formed with the Cu(II) coordinated to the pyridole nitrogen and the terminal amine. Above pH 8, [Cu(H2(555)NH2)H-2] is the most predominant species in solution. Here the Cu(II) coordinates to all four nitrogen atoms. In the solid state, a dinuclear complex, [Cu(H(55) NH3)Cl]2[Cu(H2O)2(NO3)2Cl2]H2O, was formed. Single crystal X-ray structure showed the Cu(II) to be coordinated to the pyridine and the amide N-atoms in addition to an O-atom from one of the two carbonyl groups. The coordination environment was completed by two bridged chloride ions to give a slightly distorted trigonal bipyramidal coordination geometry around the copper centre. The amine was not coordinated. The proposed sensor was successfully applied to determine copper(II) in real samples, with recoveries ranging from 10- 5 to 10-3 mol/dm-3. Using H2(555)NH2 as an optical chemical sensor emerged as a powerful tool for detecting copper(II) ions in different aqueous samples.

关键词： solution structure Optical chemical sensor UV-vis 1 H NMR and EPR spectroscopy X-ray crystallography Hirshfeld Surface Analysis

来源：评论

学校读者我要写书评

暂无评论

solution structure of the cytochrome P450 reductase-cytochrome c complex determined by neutron scattering

引用

JOURNAL OF BIOLOGICAL CHEMISTRY 2018年第14期293卷 5210-5219页

作者： Freeman, Samuel L. Martel, Anne Devos, Juliette M. Basran, Jaswir Raven, Emma L. Roberts, Gordon C. K. Univ Leicester Dept Chem Henry Wellcome BldgLancaster Rd Leicester LE1 7RH Leics England Univ Leicester Dept Mol & Cell Biol Henry Wellcome BldgLancaster Rd Leicester LE1 7RH Leics England Univ Leicester Leicester Inst Struct & Chem Biol Leicester LE1 7RH Leics England Inst Laue Langevin 71 Ave Martyrs F-38042 Grenoble France

Electron transfer in all living organisms critically relies on formation of complexes between the proteins involved. The function of these complexes requires specificity of the interaction to allow for selective electron transfer but also a fast turnover of the complex, and they are therefore often transient in nature, making them challenging to study. Here, using small-angle neutron scattering with contrast matching with deuterated protein, we report the solution structure of the electron transfer complex between cytochrome P450 reductase (CPR) and its electron transfer partner cytochrome c. This is the first reported solution structure of a complex between CPR and an electron transfer partner. The structure shows that the interprotein interface includes residues from both the FMN- and FAD-binding domains of CPR. In addition, the FMN is close to the heme of cytochrome c but distant from the FAD, indicating that domain movement is required between the electron transfer steps in the catalytic cycle of CPR. In summary, our results reveal key details of the CPR catalytic mechanism, including interactions of two domains of the reductase with cytochrome c and motions of these domains relative to one another. These findings shed light on interprotein electron transfer in this system and illustrate a powerful approach for studying solution structures of protein-protein complexes.

关键词： neutron scattering protein-protein interaction cytochrome P450 cytochrome c electron transfer protein structure cytochrome P450 reductase SANS transient complex solution structure protein structural dynamics

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：