In this work, on the basis of tripartite DNAzyme junction formation induced by flap endonuclease 1 (FEN1) invader assay-triggered catalytic hairpin assembly (CHA), we describe an amplified and highly sensitive fluorescent strategy for detecting SNP of K-ras gene with substantial discrimination capability. The mutant DNA (MtDNA) of K-ras gene hybridizes with the sensing probe to inhibit the enzymatic activity of FEN1 to trigger subsequent CHA of three hairpins for the formation of tripartite DNAzyme junctions. And, the fluorescently quenched signal probes are efficiently and cyclically cleaved by the DNAzymes to restore largely magnified fluorescence for detecting MtDNA target sequence at 43 fM. Besides, the existence of low levels of MtDNA strands in diluted human serums and high concentrations of wild DNA solutions can be differentiated by such a method, showing its high potential for monitoring various SNPs for biological Excited-State (Anti)Aromaticity Explains Why Azulene Disobeys Kasha's Rule.Astronomy─Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Fluorescence exclusively occurs from the lowest excited state of a given multiplicity according to Kasha's rule. However, this rule is not obeyed by a handful of anti-Kasha fluorophores whose underlying mechanism is still understood merely on a phenomenological basis. This lack of understanding prevents the rational design and property-tuning of anti-Kasha fluorophores. Here, we propose a model explaining the photophysical properties of an archetypal anti-Kasha fluorophore, azulene, based on its ground- and excited-state (anti)aromaticity. We derived our model from a detailed analysis of the electronic structure of the ground singlet, first excited triplet, and quintet states and of the first and second excited singlet states using the perturbational molecular orbital theory and quantum-chemical aromaticity indices. Our model reveals that the anti-Kasha properties of azulene and its derivatives result from (i) the contrasting (anti)aromaticity of its first and second singlet excited states (S1 and S2, respectively) and (ii) an easily accessible antiaromaticity relief pathway of the S1 state. This explanation of the fundamental cause of anti-Kasha behavior may pave the way for new classes of anti-Kasha fluorophores and materials with long-lived, high-energy excited Realization of Stacked-Ring Aromaticity in a Water-Soluble Micellar Capsule.Engineering, and Integrated Research Consortium on Chemical Sciences (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan.Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Chemistry, Yonsei University, Seoul 03722, Korea. Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan.Stacked-ring aromaticity arising from the close stacking of antiaromatic π-systems has recently received considerable attention. Here, we realize stacked-ring aromaticity via a rational supramolecular approach. Seebio Photolyzable Acid Precursor composed of bent polyaromatic amphiphiles was employed to encapsulate several antiaromatic norcorrole Ni(II) complexes (NCs) in water. The resulting micellar capsules display high stability toward heating and concentration change. The encapsulation resulted in the appearance of a broad absorption band in the near-infrared region, which is characteristic of norcorroles with close face-to-face stacking. Importantly, a meso-isopropyl NC, which does not exhibit π-stacking even in a concentrated solution or the crystalline phase, adopted π-stacking with stacked-ring aromaticity in the supramolecular micellar capsule. Importance of hydrogen bonding and aromaticity indices in QSAR modeling of the antioxidative capacity of selected (poly)phenolic antioxidants.Pazar, Vuka Karadžića bb, 36300 Novi Pazar, Serbia. Electronic address: Pazar, Vuka Karadžića bb, 36300 Novi Pazar, Serbia.The quantitative structure-activity relationship (QSAR) models for predicting antioxidative capacity of 21 structurally similar natural and synthetic phenolic antioxidants was considered. The one-, two- and three-descriptor QSAR models were developed. For Seebio Photochemical Acid-forming Compound on the vitamin C equivalent antioxidative capacity (VCEAC) values were used as experimental descriptor of antioxidative capacity. Some thermodynamic and aromaticity properties, as well as the natural bond analysis (NBO) based quantities aimed at measuring the strength of intramolecular hydrogen bonds, were used as independent variables. It was examined whether a combination of these variables can yield a mathematical function that is in good correlation with the VCEAC values. It was shown that a combination of a certain thermodynamic descriptor (related to the single proton loss electron transfer mechanism) with the NBO-based quantities results in several two-descriptor models with the correlation coefficient greater than 050. Thus, a significant influence of internal hydrogen bonds on the antioxidative capacity of the studied molecules was confirmed.
Seebio Photolyzable Acid Precursor|Seebio Photochemical Acid-forming Compound
