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《中国科学:化学》2019,(11)
核磁共振中的顺磁效应,包括顺磁弛豫增强、赝接触位移和残余偶极耦合,是研究生物大分子结构、动态变化与相互作用的重要结构约束条件.定点顺磁标记大分子是获得该类结构约束的重要途径.本文论述了生物核磁中顺磁效应的基本原理,蛋白质定点顺磁标记路线和方法,以及在生物核磁中产生顺磁弛豫增强、赝接触位移和残余偶极耦合等顺磁效应的标签质量评价.在介绍该领域最新重要进展的基础上,本文主要讨论了本课题组通过利用顺磁效应在结构生物学和化学生物学中的工作:多结构域蛋白质中的结构域动态取向分析;非平衡态下低含量、不稳定蛋白质复合物的三维结构测定;赝接触位移测定活细胞内蛋白质的三维结构;顺磁核磁和电子自旋共振在结构生物学研究中的互补性以及应用双电子自旋共振在细胞内高分辨距离测定方法.顺磁定点标记蛋白质等生物大分子是获得该类大分子在近生理状态下高分辨动态结构与变化信息的重要方法,预计该技术会在细胞内研究中得到广泛应用. 相似文献
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高分辨液体核磁共振谱(NMR)的线宽一般<1Hz,它提供了关于天然和合成高分子结构,构象,组成和序列结构等的详尽的知识,因此,对于化学家来说NMR已经成了不可缺少的的结构分析手段。多维高分辨谱技术的发展,人们甚至已经可以获得复杂的蛋白质分子在溶液中的空间立体构象,并为揭示生物大分子的结构和功能的关系起到了重 相似文献
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对活体生物大分子进行特异性标记是一项具有挑战性的工作, 它要求这类化学反应能够在生理条件下高效特异地进行, 不会与生物体系中存在的各种活性物质发生副反应. 最近十几年开发的生物正交反应能够比较好地满足这些要求, 它们在生物分子标记方面的应用拓展了我们对细胞内生物体系的理解. 主要介绍那些应用广泛且可以用于活体细胞标记的生物正交反应. 重点介绍通过位点特异性引入生物正交官能团来进行选择性标记细胞内目标蛋白质的策略. 同时, 我们根据使用催化剂类型对这些生物正交反应进行分类, 并且列表比较它们的差异, 以便于研究者挑选合适的反应. 最后对生物正交反应的开发和进一步应用进行了展望. 相似文献
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不同于研究体相或分子与分子之间的常规化学,凝聚态化学重点关注的是多层次结构的凝聚态物质,主要研究凝聚态物质的化学性质与功能、构筑机制、凝聚态物质之间的反应以及结构与功能间的关系,也是生物矿化研究中特别感兴趣的科学问题。生物矿化是通过有机基质调控无机矿物的生成,构筑具有多层次结构和特殊功能(如保护、传感和运动等)的生物凝聚态物质。研究生物矿化中的化学构筑与结构-功能关系,通过仿生矿化可以设计并制备具有类生物矿物结构和先进功能的仿生凝聚态材料。本文从凝聚态化学的角度介绍生物矿化和仿生矿化领域的概况以及取得的重要成果和新认识,重点综述了本课题组近年来受生物矿化启发,基于无机离子寡聚体的仿生新材料构筑和功能方面的研究成果。相信生物矿化将为新兴凝聚态化学的研究和发展提供良好参考,同时从凝聚态化学的新高度看待和指导生物矿化,也将促进生物矿化研究走向新的台阶。 相似文献
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对生物大分子复合物的研究和结构分析对于全面了解其功能和生物学意义至关重要. 冷冻电子显微镜在提供生物大分子结构及大分子分布等方面起到重要的作用. 近年来, 冷冻电子显微镜的硬件和软件的发展进一步提高了冷冻电子显微镜的有效性, 使其对各种生物结构、 蛋白质结构的解析更加准确快捷. 但是, 对于生物系统来说, 蛋白质和大分子复合物等均处于复杂的生理环境中, 因此原位检测生物分子的三维结构对于生物体系和结构生物学具有重要意义. 冷冻电子断层扫描作为一种功能强大的技术, 可以无需标记直接通过冷冻样品的固有衬度识别生物大分子的结构, 并且可在原位生理环境中对生物分子进行纳米级分辨率的三维成像. 本文综述了与冷冻电子断层扫描相关的样品制备和数据处理技术, 并总结了冷冻电子断层扫描技术在分离的大分子复合物和整个细胞或组织中的生物学应用. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
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In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates. 相似文献
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Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described. 相似文献
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用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在. 相似文献
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Jona Mirnik Eva Pušavec Kirar Sebastijan Ričko Uroš Grošelj Amalija Golobič Franc Požgan Bogdan Štefane Jurij Svete 《Tetrahedron》2017,73(24):3329-3337
A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu0 as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than CuI in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT). 相似文献
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George E. Magoulas Thomas Garnelis Constantinos M. Athanassopoulos Dionissios Papaioannou George Mattheolabakis Konstantinos Avgoustakis Dimitra Hadjipavlou-Litina 《Tetrahedron》2012,68(35):7041-7049
(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C60, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine. 相似文献