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91.
Nonenzymatic Rubylation and Ubiquitination of Proteins for Structural and Functional Studies 下载免费PDF全文
Dr. Rajesh K. Singh Adithya Sundar Prof. David Fushman 《Angewandte Chemie (International ed. in English)》2014,53(24):6120-6125
Uncovering the mechanisms that allow conjugates of ubiquitin (Ub) and/or Ub‐like (UBL) proteins such as Rub1 to serve as distinct molecular signals requires the ability to make them with native connectivity and defined length and linkage composition. A novel, effective, and affordable strategy for controlled chemical assembly of fully natural UBL–Ub, Ub–UBL, and UBL–UBL conjugates from recombinant monomers is presented. Rubylation of Ub and Rub1 and ubiquitination of Rub1 was achieved without E2/E3 enzymes. New residue‐specific information was obtained on the interdomain contacts in naturally‐occurring K48‐linked Rub1–Ub and Ub–Rub1, and K29‐linked Rub1–Ub heterodimers, and their recognition by a K48‐linkage‐specific Ub receptor. The disassembly of these heterodimers by major deubiquitinating enzymes was examined and it was discovered that some deubiquitinases also possess derubylase activity. This unexpected result suggests possible crosstalk between Ub and Rub1/Nedd8 signaling pathways. 相似文献
92.
Sardar PS Maity SS Ghosh S Chatterjee J Maiti TK Dasgupta S 《The journal of physical chemistry. B》2006,110(42):21349-21356
Human placental ribonuclease inhibitor (hRI) containing six tryptophan (Trp) residues located at positions 19, 261, 263, 318, 375, and 438 and its complex with RNase A have been studied using steady-state and time-resolved fluorescence (298 K) as well as low-temperature phosphorescence (77 K). Two Trp residues in wild-type hRI and also in the protein-protein complex with RNase A are resolved optically. The accessible surface area values of Trp residues in the wild-type hRI and its complex and consideration of inter-Trp energy transfer in the wild-type hRI reveal that one of the Trp residues is Trp19, which is located in a hydrophobic buried region. The other Trp residue is tentatively assigned as Trp375 based on experimental results on wild-type hRI and its complex. This residue in the wild-type hRI is more or less solvent exposed. Both the Trp residues are perturbed slightly on complex formation. Trp19 moves slightly toward a more hydrophobic region, and the environment of Trp375 becomes less solvent exposed. The complex formation also results in a more heterogeneous environment for both the optically resolved Trp residues. 相似文献
93.
Ibrahim Abdul Razak S. Shanmuga Sundara Raj Hoong‐Kun Fun Ye‐Xiang Tong Zhong‐Lin Lu Bei‐Sheng Kang 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(3):291-292
In the crystal structure of the title compound, [Zn(C4H13N3)2]2[Fe(CN)6]·4H2O, the asymmetric unit is formed by a [Zn(dien)2]2+ cation (dien = diethylenetriamine, NH2CH2CH2NHCH2CH2NH2), water molecules and half of the [Fe(CN)6]4? anion which is related by inversion symmetry through the Fe atom. The geometry around the Zn and Fe atoms is distorted octahedral and octahedral, respectively. Intramolecular O—H?O hydrogen bonds involving the water molecules, and intermolecular O—H?N hydrogen bonds involving the water molecules and the anions, result in an infinite chain. Intramolecular O—H?O and N—H?N, and intermolecular O—H?N, N—H?O and N—H?N hydrogen bonds form a three‐dimensional framework. 相似文献
94.
Zhong‐Lin Lu Wen Xiao Zhong‐Ning Chen Xiao‐Yang Gong S. Shanmuga Sundara Raj Ibrahim Abdul Razak Hoong‐Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):1017-1018
The title compound, C18H12N4O·H2O, adopts the keto tautomeric form and the azomethine C=N double bond is in the E configuration. The dihedral angle between the planes of the diazafluorene moiety and the phenyl ring is 11.3 (1)°. In the solid state, the molecules form infinite chain‐like structures via O—H?N hydrogen bonds involving the water molecules and diazafluorene moieties. 相似文献
95.
Fangfang Jian Fengli Bei Lude Lu Xujie Yang Xin Wang Ibrahim Abdul Razak S. Shanmuga Sundara Raj Hoong‐Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):e288-e289
In the title compound, [Cu(C5H10NO2S2)(C18H15P)2]·C18H15P, the Cu atom is in a distorted tetrahedral coordination, with two triphenylphosphine P atoms and two S atoms from an N,N‐bis(2‐hydroxyethyl)dithiocarbamate ligand occupying the vertices. The crystal structure is characterized by alternate layers of complex and triphenylphosphine molecules. 相似文献
96.
The kinetics and mechanism of Ag(I)-catalyzed oxidation of l-alanine by cerium (IV) in sulfuric acid media have been investigated by titrimetric technique of redox in the temperature range of 298–313 K. It is found that the reaction is of first order with respect to Ce(IV) and l-alanine, and it is of a positive fractional order with respect to Ag(I). It is found that the pseudo first order ([l-alanine] ? [Ce(IV)] ? [Ag(I)]) rate constant k′ increases with the increase of[H+]. The major oxidation product of alanine has been identified as acetaldehyde by an 1H NMR and IR spectroscopy. Under the experimental conditions, the kinetically active species has been found to be Ce4+. Under nitrogen atmosphere, the reaction system can initiate the polymerization of acrylonitrile, indicating generation of free radicals. On the basis of the experimental results, a suitable mechanism has been proposed. The rate constants of the rate-determining step together with the activation parameters were evaluated. 相似文献
97.
Ramendra Sundar Dey Raj Kumar Bera C. R. Raj 《Analytical and bioanalytical chemistry》2013,405(11):3431-3448
Functional nanomaterials have emerged as promising candidates in the development of an amperometric sensing platform for the detection and quantification of bioanalytes. The remarkable characteristics of nanomaterials based on metal and metal oxide nanoparticles, carbon nanotubes, and graphene ensure enhanced performance of the sensors in terms of sensitivity, selectivity, detection limit, response time, and multiplexing capability. The electrocatalytic properties of these functional materials can be combined with the biocatalytic activity of redox enzymes to develop integrated biosensing platforms. Highly sensitive and stable miniaturized amperometric sensors have been developed by integrating the nanomaterials and biocatalyst with the transducers. This review provides an update on recent progress in the development of amperometric sensors/biosensors using functional nanomaterials for the sensing of clinically important metabolites such as glucose, cholesterol, lactate, and glutamate, immunosensing of cancer biomarkers, and genosensing. 相似文献
98.
Raj A. Sundar Lon J. Mathias 《Journal of polymer science. Part A, Polymer chemistry》1994,32(15):2825-2839
4-Hydroxy-5-nitrophthalimides were produced via nucleophilic aromatic substitution (NAS) of 4,5-dichloro phthalimide substituents by potassium nitrite. The use of a N-phenyl-phthalimide having a protected 4′-hydroxyl group allows concurrent deprotection and nitro reduction to amine to give the 4-hydroxy-5-amino-N-(4′-hydroxyphenyl) phthalimide. This key intermediate is the precursor to a poly (ether-imide-benzoxazole), and is the condensable monomer for a poly (ester-imide-benzoxazole). Benzoxazole monomer formation via condensation with p-fluorobenzoyl chloride afforded 2-(4′-fluorophenyl)-5,6,-N-[4′(-hydroxyphenyl) imide]-benzoxazole, which was polymerized under NAS conditions to produce a poly(ether-imide-benzoxazole) having an endothermic transition at 454°C with weight retention of 90% at 500°C in both air and nitrogen. Solution polycondensation of the 4-hydroxy-5-amino-N-(4′-hydroxyphenyl) phthalimide monomer with isophthaloyl chloride afforded a poly(ester-amide-imide) which was isolated and thermally cyclodehydrated in the solid state under vacuum to give a poly(ester-imide-benzoxazole) having 95% weight retention at 500°C in both air and nitrogen, with no detectable DSC transitions up to 500°C. © 1994 John Wiley & Sons, Inc. 相似文献
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