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Nature Chemistry

Yansong Zhou, Fanglin Che, Min Liu, Chengqin Zou, Zhiqin Liang, Phil De Luna, Haifeng Yuan, Jun Li, Zhiqiang Wang, Haipeng Xie, Hongmei Li, Peining Chen, Eva Bladt, Rafael Quintero-Bermudez, Tsun-Kong Sham, Sara Bals, Johan Hofkens, David Sinton, Gang Chen, Edward H Sargent
The electrochemical reduction of CO2 to multi-carbon products has attracted much attention because it provides an avenue to the synthesis of value-added carbon-based fuels and feedstocks using renewable electricity. Unfortunately, the efficiency of CO2 conversion to C2 products remains below that necessary for its implementation at scale. Modifying the local electronic structure of copper with positive valence sites has been predicted to boost conversion to C2 products. Here, we use boron to tune the ratio of Cuδ+ to Cu0 active sites and improve both stability and C2 -product generation...
July 16, 2018: Nature Chemistry
Eugene E Kwan, Yuwen Zeng, Harrison A Besser, Eric N Jacobsen
Nucleophilic aromatic substitution (SN Ar) is one of the most widely applied reaction classes in pharmaceutical and chemical research, providing a broadly useful platform for the modification of aromatic ring scaffolds. The generally accepted mechanism for SN Ar reactions involves a two-step addition-elimination sequence via a discrete, non-aromatic Meisenheimer complex. Here we use 12 C/13 C kinetic isotope effect (KIE) studies and computational analyses to provide evidence that prototypical SN Ar reactions in fact proceed through concerted mechanisms...
July 16, 2018: Nature Chemistry
Tianfei Liu, Meiyuan Guo, Andreas Orthaber, Reiner Lomoth, Marcus Lundberg, Sascha Ott, Leif Hammarström
Metal hydrides are key intermediates in catalytic proton reduction and dihydrogen oxidation. There is currently much interest in appending proton relays near the metal centre to accelerate catalysis by proton-coupled electron transfer (PCET). However, the elementary PCET steps and the role of the proton relays are still poorly understood, and direct kinetic studies of these processes are scarce. Here, we report a series of tungsten hydride complexes as proxy catalysts, with covalently attached pyridyl groups as proton acceptors...
July 16, 2018: Nature Chemistry
Irina Yarulina, Kristof De Wispelaere, Simon Bailleul, Joris Goetze, Mike Radersma, Edy Abou-Hamad, Ina Vollmer, Maarten Goesten, Brahim Mezari, Emiel J M Hensen, Juan S Martínez-Espín, Magnus Morten, Sharon Mitchell, Javier Perez-Ramirez, Unni Olsbye, Bert M Weckhuysen, Veronique Van Speybroeck, Freek Kapteijn, Jorge Gascon
In the version of this Article originally published, on the right side of Fig. 4b, the 'Aromatic cycle' label was erroneously shifted outside of the central circular arrow into a position on part of the reaction cycle. This has been corrected in the online versions of the Article.
July 10, 2018: Nature Chemistry
Alanna Schepartz
In the News & Views 'Foldamers wave to the ribosome', multiple changes to the main text were required. In paragraph 2 "whose monomer sequence is truly defined" should have read "whose monomer sequence is both diverse and truly defined" and "Truly sequence-defined..." should have read "Diverse and truly sequence defined…". In the penultimate paragraph, 'appendages 5-9' should have been "appendages 5 and 7-9"; in the sentence starting "Based on these criteria...
July 10, 2018: Nature Chemistry
Mohammad M Sultan, Gert Kiss, Vijay S Pande
Kinases are ubiquitous enzymes involved in the regulation of critical cellular pathways. However, in silico modelling of the conformational ensembles of these enzymes is difficult due to inherent limitations and the cost of computational approaches. Recent algorithmic advances combined with homology modelling and parallel simulations have enabled researchers to address this computational sampling bottleneck. Here, we present the results of molecular dynamics studies for seven Src family kinase (SFK) members: Fyn, Lyn, Lck, Hck, Fgr, Yes and Blk...
July 9, 2018: Nature Chemistry
Han Yong Bae, Denis Höfler, Philip S J Kaib, Pinar Kasaplar, Chandra Kanta De, Arno Döhring, Sunggi Lee, Karl Kaupmees, Ivo Leito, Benjamin List
The chemical synthesis of organic molecules involves, at its very essence, the creation of carbon-carbon bonds. In this context, the aldol reaction is among the most important synthetic methods, and a wide variety of catalytic and stereoselective versions have been reported. However, aldolizations yielding tertiary aldols, which result from the reaction of an enolate with a ketone, are challenging and only a few catalytic asymmetric Mukaiyama aldol reactions with ketones as electrophiles have been described...
July 9, 2018: Nature Chemistry
Michael A Tarselli
The original version of this In Your Element contained some inaccuracies regarding the stability of fermium, cold and hot fusion techniques, the naming process and chemical investigations; see the correction notice for details.
July 4, 2018: Nature Chemistry
Ivana Drienovská, Clemens Mayer, Christopher Dulson, Gerard Roelfes
Creating designer enzymes with the ability to catalyse abiological transformations is a formidable challenge. Efforts toward this goal typically consider only canonical amino acids in the initial design process. However, incorporating unnatural amino acids that feature uniquely reactive side chains could significantly expand the catalytic repertoire of designer enzymes. To explore the potential of such artificial building blocks for enzyme design, here we selected p-aminophenylalanine as a potentially novel catalytic residue...
July 2, 2018: Nature Chemistry
Niko Pavliček, Przemyslaw Gawel, Daniel R Kohn, Zsolt Majzik, Yaoyao Xiong, Gerhard Meyer, Harry L Anderson, Leo Gross
Rearrangements that change the connectivity of a carbon skeleton are often useful in synthesis, but it can be difficult to follow their mechanisms. Scanning probe microscopy can be used to manipulate a skeletal rearrangement at the single-molecule level, while monitoring the geometry of reactants, intermediates and final products with atomic resolution. We studied the reductive rearrangement of 1,1-dibromo alkenes to polyynes on a NaCl surface at 5 K, a reaction that resembles the Fritsch-Buttenberg-Wiechell rearrangement...
July 2, 2018: Nature Chemistry
Mijanur Rahaman Molla, Poornima Rangadurai, Lucas Antony, Subramani Swaminathan, Juan J de Pablo, S Thayumanavan
In the version of this Article originally published, multiple changes to the "Results and discussion" section were required. In paragraph 1, "(Supplementary Fig. 1)" should have read "(Fig. 1e-j and Supplementary Fig. 1)"; in the first sentence of paragraph 3, "(R6G)" should have read "(R6G, Fig. 2i)"; in paragraph 6 in the sentence beginning "Temporal release of hydrophilic...", Supplementary Fig. 4 should have been cited after "360 nm"; in paragraph 9, in the sentence beginning "To test this...
June 28, 2018: Nature Chemistry
Jianchun Wang, Renhe Li, Zhe Dong, Peng Liu, Guangbin Dong
Achieving site-selectivity in arene functionalization that is complementary to the site-selectivity from electrophilic aromatic substitution reactions has been a long-standing quest in organic synthesis. Palladium/norbornene cooperative catalysis potentially offers a unique approach to this problem, but its use has been hampered by the ortho constraint, which is the requirement of an ortho substituent for mono ortho functionalization of haloarenes. Here, we show that such a challenge could be addressed using a new class of bridgehead-modified norbornenes, thereby enabling a broadly useful strategy for arene functionalization with complementary site-selectivity...
June 25, 2018: Nature Chemistry
Irina Yarulina, Kristof De Wispelaere, Simon Bailleul, Joris Goetze, Mike Radersma, Edy Abou-Hamad, Ina Vollmer, Maarten Goesten, Brahim Mezari, Emiel J M Hensen, Juan S Martínez-Espín, Magnus Morten, Sharon Mitchell, Javier Perez-Ramirez, Unni Olsbye, Bert M Weckhuysen, Veronique Van Speybroeck, Freek Kapteijn, Jorge Gascon
The combination of well-defined acid sites, shape-selective properties and outstanding stability places zeolites among the most practically relevant heterogeneous catalysts. The development of structure-performance descriptors for processes that they catalyse has been a matter of intense debate, both in industry and academia, and the direct conversion of methanol to olefins is a prototypical system in which various catalytic functions contribute to the overall performance. Propylene selectivity and resistance to coking are the two most important parameters in developing new methanol-to-olefin catalysts...
June 25, 2018: Nature Chemistry
Alex P S Brogan, Liem Bui-Le, Jason P Hallett
The increasing requirement to produce platform chemicals and fuels from renewable sources means advances in biocatalysis are rapidly becoming a necessity. Biomass is widely used in nature as a source of energy and as chemical building blocks. However, recalcitrance towards traditional chemical processes and solvents provides a significant barrier to widespread utility. Here, by optimizing enzyme solubility in ionic liquids, we have discovered solvent-induced substrate promiscuity of glucosidase, demonstrating an unprecedented example of homogeneous enzyme bioprocessing of cellulose...
June 25, 2018: Nature Chemistry
Kevin J McDonnell, Joseph A Chemler, Phillip L Bartels, Elizabeth O'Brien, Monica L Marvin, Janice Ortega, Ralph H Stern, Leon Raskin, Guo-Min Li, David H Sherman, Jacqueline K Barton, Stephen B Gruber
The human DNA repair enzyme MUTYH excises mispaired adenine residues in oxidized DNA. Homozygous MUTYH mutations underlie the autosomal, recessive cancer syndrome MUTYH-associated polyposis. We report a MUTYH variant, p.C306W (c.918C>G), with a tryptophan residue in place of native cysteine, that ligates the [4Fe4S] cluster in a patient with colonic polyposis and family history of early age colon cancer. In bacterial MutY, the [4Fe4S] cluster is redox active, allowing rapid localization to target lesions by long-range, DNA-mediated signalling...
June 18, 2018: Nature Chemistry
Sergey P Laptenok, Agnieszka A Gil, Christopher R Hall, Andras Lukacs, James N Iuliano, Garth A Jones, Gregory M Greetham, Paul Donaldson, Atsushi Miyawaki, Peter J Tonge, Stephen R Meech
Photochromic fluorescent proteins play key roles in super-resolution microscopy and optogenetics. The light-driven structural changes that modulate the fluorescence involve both trans-to-cis isomerization and proton transfer. The mechanism, timescale and relative contribution of chromophore and protein dynamics are currently not well understood. Here, the mechanism of off-to-on-state switching in dronpa is studied using femtosecond-to-millisecond time-resolved infrared spectroscopy and isotope labelling. Chromophore and protein dynamics are shown to occur on multiple timescales, from picoseconds to hundreds of microseconds...
June 11, 2018: Nature Chemistry
Kyle F Biegasiewicz, Simon J Cooper, Megan A Emmanuel, David C Miller, Todd K Hyster
Strategies that provide enzymes with the ability to catalyse non-natural reactions are of considerable synthetic value. Photoredox catalysis has proved adept at expanding the synthetic repertoire of existing catalytic platforms, yet, in the realm of biocatalysis it has primarily been used for cofactor regeneration. Here we show that photoredox catalysts can be used to enable new catalytic function in nicotinamide-dependent enzymes. Under visible-light irradiation, xanthene-based photocatalysts enable a double-bond reductase to catalyse an enantioselective deacetoxylation...
June 11, 2018: Nature Chemistry
Hojoon Park, Pritha Verma, Kai Hong, Jin-Quan Yu
The development of a Pd(II)-catalysed enantioselective fluorination of C(sp3 )-H bonds would offer a new approach to making chiral organofluorines. However, such a strategy is particularly challenging because of the difficulty in differentiating prochiral C(sp3 )-H bonds through Pd(II)-insertion, as well as the sluggish reductive elimination involving Pd-F bonds. Here, we report the development of a Pd(II)-catalysed enantioselective C(sp3 )-H fluorination using a chiral transient directing group strategy. In this work, a bulky, amino amide transient directing group was developed to control the stereochemistry of the C-H insertion step and selectively promote the C(sp3 )-F reductive elimination pathway from the Pd(IV)-F intermediate...
June 11, 2018: Nature Chemistry
Julian C W Willis, Jason W Chin
Genetically encoding distinct non-canonical amino acids (ncAAs) into proteins synthesized in cells requires mutually orthogonal aminoacyl-tRNA synthetase (aaRS)/tRNA pairs. The pyrrolysyl-tRNA synthetase/Pyl tRNA pair from Methanosarcina mazei (Mm) has been engineered to incorporate diverse ncAAs and is commonly considered an ideal pair for genetic code expansion. However, finding new aaRS/tRNA pairs that share the advantages of the MmPylRS/MmPyl tRNA pair and are orthogonal to both endogenous aaRS/tRNA pairs and the MmPylRS/MmPyl tRNA pair has proved challenging...
May 28, 2018: Nature Chemistry
Devon R Widmer, Benjamin J Schwartz
For solution-phase chemical reactions, the solvent is often considered simply as a medium to allow the reactants to encounter each other by diffusion. Although examples of direct solvent effects on molecular solutes exist, such as the compression of solute bonding electrons due to Pauli repulsion interactions, the solvent is not usually considered a part of the chemical species of interest. We show, using quantum simulations of Na2 , that when there are local specific interactions between a solute and solvent that are energetically on the same order as a hydrogen bond, the solvent controls not only the bond dynamics but also the chemical identity of the solute...
May 21, 2018: Nature Chemistry
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