3,020 research outputs found
Defluorinative C–C Bond-Forming Reaction of Trifluoromethyl Alkenes with <i>gem</i>-(Diborylalkyl)lithiums
No full textWe report the transition-metal-free defluorinative C-C bond-forming reaction of trifluoromethyl alkenes with gem-(diborylalkyl)lithiums. This synthetic strategy provides access to a variety of 4,4-difluoro homoallylic diboronate esters, which serve as versatile intermediates in the efficient preparation of valuable gem-difluoroalkene derivatives. Further synthetic modifications are conducted to demonstrate the synthetic utility of the obtained 4,4-difluoro homoallylic diboronate esters. © 2022 American Chemical Society. All rights reserved.11Nsciescopu
Deep mutational scanning of Escherichia coli Flavin mononucleotide binding fluorescent protein for the funtion and sequence relationship
No full textSequence and function relationship of Escherichia coli flavin mononucleotide binding fluorescent protein
No full textFlavin mononucleotide (FMN)-binding fluorescent proteins can provide in vivo reporter system, without oxygen. Here, we present the functional landscape of individual amino acid sequence of Escherichia coli FMN-binding fluorescent protein (EcFbFP). We used random mutagenesis to generate the mutant libraries, which were screened by function loss or retained. The function and sequence relationship of the mutants were analyzed in single high-throughput sequencing, resulting in 329 tolerant mutations and 259 sensitive mutations that show retained fluorescence or loss of fluorescence respectively. In addition, the enrichment of tolerant or sensitive mutations in each amino acid residues were weighed to find functionally important residues n EcFbFP. The mutation enrichment analysis show that the positions critical to the function of EcFbFP lies among the FMN binding pocket, turns and loops of the protein where dynamic conformational changes occur and the Glu56-Lys97 salt bridge which is critical to structural stability of EcFbFP. Collectively, the mutational scanning results provide a functional landscape of each amino acid of EcFbFP
Draft Genome Sequence of an Acid-Tolerant Clostridium drakei SL1, a Potential Chemical Producer through Syngas Fermentation
No full textStereoselective Access to Tetra‐ and Tri‐Substituted Fluoro‐ and Chloro‐borylalkenes via Boron‐Wittig Reaction
No full textReported herein is the efficient synthesis of tetra- and tri-substituted ( Z )-fluoro- and ( Z )-chloro-borylalkenes by the Boron–Wittig reaction of ketones and aldehydes with bench-top stable halo-diborylmethanes. The substrate scope is broad and the Boron–Wittig reaction proceeds from a diverse range of ketones and aldehydes including biologically relevant molecules with fluoro- or chloro-diborylmethanes, providing tetra- and tri-substituted ( Z )-fluoro- and ( Z )-chloro-borylalkenes in good yields with high stereoselectivity. The utilities of the obtained ( Z )-fluoro- and ( Z )-chloro-borylalkenes are highlighted by further modifications to afford fluoroalkene derivatives or all-carbon substituted alkene.11Nsciescopu
Erratum: 3D bioprinted in vitro secondary hyperoxaluria model by mimicking intestinal-oxalatemalabsorption-related kidney stone disease (Applied Physics Reviews (2022) 9 (041408) DOI: 10.1063/5.0087345)
No full text© 2023 Author(s).This article was originally published online on 21 November 2022 with an incorrect affiliation identifier for author Dong-Woo Cho. It is correct as it appears above. All online versions of this article were corrected on 23 November 2022. AIP Publishing apologizes for this error.11Nsciescopu
Unimodality of Betti numbers for Hamiltonian circle actions with index-increasing moment Maps
No full textThe unimodality conjecture posed by Tolman in [L. Jeffrey, T. Holm, Y. Karshon, E. Lerman and E. Meinrenken, Moment maps in various geometries, http://www.birs.ca/workshops/2005/05w5072/report05w5072.pdf] states that if (M,ω) is a 2n-dimensional smooth compact symplectic manifold equipped with a Hamiltonian circle action with only isolated fixed points, then the sequence of Betti numbers {b0(M),b2(M),...,b2n(M)} is unimodal, i.e. bi(M) ≤ bi+2(M) for every i < n. Recently, the author and Kim [Y. Cho and M. Kim, Unimodality of the Betti numbers for Hamiltonian circle action with isolated fixed points, Math. Res. Lett. 21(4) (2014) 691-696] proved that the unimodality holds in eight-dimensional case by using equivariant cohomology theory. In this paper, we generalize the idea in [Y. Cho and M. Kim, Unimodality of the Betti numbers for Hamiltonian circle action with isolated fixed points, Math. Res. Lett. 21(4) (2014) 691-696] to an arbitrary dimensional case. We prove the conjecture in arbitrary dimension under the assumption that the moment map H : M → R is index-increasing, which means that ind(p) < ind(q) implies H(p) < H(q) for every pair of critical points p and q of H, where ind(p) is the Morse index of p with respect to H. © World Scientific Publishing Company1111sciescopu
Single-molecule imaging reveals the mechanism underlying histone loading of Schizosaccharomyces Pombe AAA+ ATPase Abo1
No full textChromatin dynamics is essential for maintaining genomic integrity and regulating gene expression. Conserved bromodomain-containing AAA+ ATPases play important roles in nucleosome organization as histone chaperones. Recently, the high-resolution cryo-electron microscopy structures of Schizosaccharomyces pombe Abo1 revealed that it forms a hexameric ring and undergoes a conformational change upon ATP hydrolysis. In addition, single-molecule imaging demonstrated that Abo1 loads H3-H4 histones onto DNA in an ATP hydrolysisdependent manner. However, the molecular mechanism by which Abo1 loads histones remains unknown. Here, we investigated the details concerning Abo1-mediated histone loading onto DNA and the Abo1- DNA interaction using single-molecule imaging techniques and biochemical assays. We show that Abo1 does not load H2A-H2B histones. Interestingly, Abo1 deposits multiple copies of H3-H4 histones as the DNA length increases and requires at least 80 bp DNA. Unexpectedly, Abo1 weakly binds DNA regardless of ATP, and neither histone nor DNA stimulates the ATP hydrolysis activity of Abo1. Based on our results, we propose an allosteric communication model in which the ATP hydrolysis of Abo1 changes the configuration of histones to facilitate their deposition onto DNA
Demonstration of Ge pMOSFETs with 6 Å EOT using TaN/ZrO2/Zr-cap/n-Ge(100) gate stack fabricated by novel vacuum annealing and in-situ metal capping method
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