Recognition of Flexible Peptides in Water by Transition Metal Complexes
摘要:
[GRAPHICS]This paper describes the design, synthesis, and evaluation of transition metal complexes capable of recognizing flexible histidine-containing peptides in aqueous medium (25 mM HEPES buffer, pH = 7.0, 25 degrees C). When the pattern of metal ions on a complex matches with the pattern of histidine moieties on the peptide, strong interaction (K = 1.2 x 10(6) M-1) can be achieved. The complex was highly selective (>200:1) in discriminating similar flexible peptides differing only by one glycine unit.
A Positional Scanning Approach to the Discovery of Dipeptide-Based Catalysts for the Enantioselective Addition of Vinylzinc Reagents to Aldehydes
作者:Christopher M. Sprout、Meaghan L. Richmond、Christopher T. Seto
DOI:10.1021/jo051342w
日期:2005.9.1
crude form as catalysts for the asymmetric addition of vinylzinc reagents to aldehydes to give chiralallylicalcohols. Three sites of diversity on the ligands were optimized using a positional scanning approach. The optimized structure from the library, ligand 54, was found to catalyze the formation of 10 different (E)-allylicalcohols with enantioselectivities ranging from 90% to 95% ee. This ligand was
Regio‐ and Stereoselective Chan‐Lam‐Evans Enol Esterification of Carboxylic Acids with Alkenylboroxines
作者:Luuk Steemers、Linda Wijsman、Jan H. van Maarseveen
DOI:10.1002/adsc.201800914
日期:2018.11.5
Efficient and scalable Cu(II)‐mediated enol esterification methodology of carboxylicacids from alkenyl boroxines and boronic acids is presented. The reaction shows a wide scope in aliphatic and aromatic carboxylicacids in combination with several alkenyl boroxines. In the case of 2‐substituted alkenyl boroxines the double bond configuration was fully retained in the enol ester product. Also N‐hydroxyimides
Discovery of N-{3-[(ethanimidoylamino)methyl]benzyl}-l-prolinamide dihydrochloride: A new potent and selective inhibitor of the inducible nitric oxide synthase as a promising agent for the therapy of malignant glioma
作者:Cristina Maccallini、Mauro Di Matteo、Marialucia Gallorini、Monica Montagnani、Valentina Graziani、Alessandra Ammazzalorso、Pasquale Amoia、Barbara De Filippis、Sara Di Silvestre、Marialuigia Fantacuzzi、Letizia Giampietro、Maria A. Potenza、Nazzareno Re、Assunta Pandolfi、Amelia Cataldi、Rosa Amoroso
DOI:10.1016/j.ejmech.2018.04.027
日期:2018.5
aberrant iNOS induction may have detrimental consequences, and seems to be involved in the proliferation and progression of different tumors, such as malignant gliomas. Therefore, selectiveinhibition of iNOS could represent a feasible therapeutic strategy to treat these conditions. In this context, we have previously disclosed new acetamidines able to inhibit iNOS with a very high selectivity profile
Modeling Thioredoxin Reductase‐Like Activity with Cyclic Selenenyl Sulfides: Participation of an NH⋅⋅⋅Se Hydrogen Bond through Stabilization of the Mixed Se−S Intermediate
generated mixedSe-Sintermediate. However, it is not clear how the kinetically unfavorable second step progresses smoothly in the catalytic cycle. A model study that used synthetic selenenylsulfides, which mimic the active site structure of human TrxR comprising Cys497, Sec498, and His472, suggested that His472 can play a key role by forming a hydrogenbond with the Se atom of the mixedSe-S intermediate
在硫氧还蛋白还原酶(TrxR)的氧化还原活性中心,Cys497和Sec498之间形成硒烯基硫键(Se-S),通过与附近的二硫醇反应将其激活为硫代硒烯酸酯状态([SH,Se-])。存在于另一个亚基中的基序([SHCys59,SHCys64])。该过程通过两个可逆的步骤完成:Cys59的半胱氨酸硫醇对Se-S键的Se原子的攻击,以及剩余硫醇对所生成的混合Se-S中间体的S原子的后续攻击。然而,尚不清楚动力学上不利的第二步骤如何在催化循环中顺利进行。使用合成的硒烯基硫化物进行模型研究,该硫化物模拟人TrxR的活性位点结构,包括Cys497,Sec498和His472,提示His472可以通过与混合的Se-S中间体的Se原子形成氢键来促进第二步,从而发挥关键作用。另外,硒烯基硫化物在培养的细胞中表现出针对H 2 O 2诱导的氧化应激的防御能力,这表明药物应用可控制细胞中的氧化还原平衡。
Modeling Type‐1 Iodothyronine Deiodinase with Peptide‐Based Aliphatic Diselenides: Potential Role of Highly Conserved His and Cys Residues as a General Acid Catalyst
Type-1 iodothyroninedeiodinase, which promotes the deiodination of iodine atoms on the outer and inner rings of thyroxine, was successfully modeled using a peptide-based selenocompound. Kinetic analyses of this reaction suggested that highly conserved His and Cys residues at the active site crucially act as general acid catalysts together with the selenocysteine redox center.
1 型碘甲腺原氨酸脱碘酶可促进甲状腺素外环和内环上的碘原子脱碘,该酶已使用基于肽的硒化合物成功建模。该反应的动力学分析表明,活性位点上高度保守的 His 和 Cys 残基与硒代半胱氨酸氧化还原中心一起作为一般酸催化剂起着至关重要的作用。