Review
Chemistry, Multidisciplinary
Peng Sang, Jianfeng Cai
Summary: Unnatural helical peptidic foldamers are attracting attention due to their unique folding behaviors, diverse protein binding mechanisms, and promising applications in various fields. They are comprised of well-defined backbone conformers with unusual structural parameters and can exhibit intriguing three-dimensional helical structures. These foldamers have superior resistance to degradation, enhanced bioavailability, and improved chemodiversity, making them potential mimics of protein helical segments.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Biochemistry & Molecular Biology
Bankala Krishnarjuna, Thirupathi Ravula, Edgar M. Faison, Marco Tonelli, Qi Zhang, Ayyalusamy Ramamoorthy
Summary: In this study, polymer-based nanodiscs were used to measure RDCs from nucleic acids. The nanodiscs were characterized and their alignment stability was confirmed. RDCs from a labeled nucleic acid molecule were successfully measured using the aligned nanodiscs. This demonstrates the potential of SMA-EA-based lipid-nanodiscs for structural and dynamical studies of nucleic acids.
Article
Chemistry, Physical
Yuxin Jiang, Hai-Feng Chen
Summary: Intrinsically disordered proteins (IDPs) play a crucial role in various human diseases. Molecular dynamics simulation is an important tool for studying the conformer distribution of IDPs, but its accuracy relies on the utilization of a precise force field. A recent study developed a CMAP optimized force field (ff03CMAP) that shows better performance in sampling diverse conformers for IDPs and stabilizing the conformers of ordered proteins compared to the ff03 force field.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Qi Lin, Hao Lan, Chunmiao Ma, Ryan T. Stendall, Kenneth Shankland, Rebecca A. Musgrave, Peter N. Horton, Carsten Baldauf, Hans-Joerg Hofmann, Craig P. Butts, Manuel M. Mueller, Alexander J. A. Cobb
Summary: We present the first structures of an unusual helix formed by a heteromeric sequence of alpha- and delta-amino acids and demonstrate its application in catalysis. The helix formation is driven by intramolecular hydrogen bonds, but we also observed an apolar interaction that stabilizes one type of helix over another. This unique stabilization enables the alpha-residues to engage in bifunctional catalysis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Michael Reggelin, Stefan Immel
Summary: The study investigates the impact of vibrational analysis on the accuracy of back-calculating RDCs from molecular models, and the effects of thermal motions on the differentiability of diastereomers.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Sinead McCann, William E. Roe, Hannah E. Agnew, Peter C. Knipe
Summary: To imitate the dynamic molecules in biological systems, foldamers need to possess stimulus-responsive behavior. In this study, we present a foldamer architecture based on alternating pyridine-diketopiperazine linkers. Epimerization is prevented via a copper-catalyzed coupling protocol. The native conformation of the compounds is initially investigated in both solid and solution states. The foldamers can be solubilized in DMSO and pH 9.5 buffer while retaining conformational control. Furthermore, dynamic switching is demonstrated through acid treatment, resulting in stimulus-responsive sidechain reconfiguration.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Kathleen A. Farley, Martin R. M. Koos, Ye Che, Reto Horst, Chris Limberakis, Justin Bellenger, Ricardo Lira, Leandro F. Gil-Silva, Roberto R. Gil
Summary: This study presents a novel gel for aligning small organic molecules and cyclic peptides in water, which has been proven effective in molecular conformation analysis. The identification of minor conformers that cannot be easily determined by conventional methods will facilitate the use of RDC experiments in structure-based drug design.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Bathini Veeraprakash, Abdul K. J. Shanavas, Goddeti S. M. Reddy, Nitin P. Lobo, Krishna V. Ramanathan, Tanneru Narasimhaswamy
Summary: The conformations of mesogens in the liquid crystalline phase were investigated using C-13 solid-state NMR, revealing different order parameter values for the phenyl rings of different molecules. By comparing with the ordering of rod-like mesogens, the average conformations of other mesogens were proposed.
Article
Chemistry, Multidisciplinary
Sirine Nouri, Julien Boudet, Hiang Dreher-Teo, Frederic H. -T. Allain, Rudi Glockshuber, Loic Salmon, Christoph Giese
Summary: In NMR spectroscopy, residual dipolar couplings (RDCs) are highly accurate probes for investigating biological structure and dynamics. Type 1 pili, derived from bacteria, are introduced as an alternative liquid-crystalline alignment medium for measuring RDCs. By elongating wild-type pili, the medium is made suitable for efficient NMR sample preparation. Additionally, type 1 pili demonstrate compatibility with challenging experimental conditions, making them a valuable alternative to traditional alignment media in NMR studies.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Patrick M. Killoran, George S. M. Hanson, Sanne J. M. Verhoork, Madeleine Smith, Davide Del Gobbo, Lu-Yun Lian, Christopher R. Coxon
Summary: A method using 4-fluorophenylalanine as a reporter group for F-19 NMR was developed to measure the conformational status of peptidylprolyl bonds in peptide models. This method was applied to study the prolyl bond status in pentapeptide models of the intrinsically disordered region of alpha-synuclein. It was demonstrated that F-19 NMR is a valuable tool for studying proline isomerism under different conditions.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Pablo Tovillas, Claudio D. Navo, Paula Oroz, Alberto Avenoza, Francisco Corzana, Maria M. Zurbano, Gonzalo Jimenez-Oses, Jesus H. Busto, Jesus Peregrina
Summary: Chiral bicyclic N,O-acetal isoserine derivatives have been synthesized using acid-catalyzed reactions, which have significant applications in peptidomimetic and medicinal chemistry.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Martin D. Gelenter, Ad Bax
Summary: Post-translational modifications are commonly found in eukaryotic proteomes. However, these modifications are rarely studied using NMR in eukaryotic proteins, which are usually produced in E. coli through recombinant expression. The native C-terminal amide of melittin, a major peptide in honey bee venom, significantly affects its structure and dynamics. This study presents a method to produce isotopically labeled native melittin through recombinant expression and chemical amidation. It also confirms the accuracy of structural models generated by AlphaFold-Multimer using experimental residual dipolar couplings.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Bibhuti Bhusana Palai, Nagendra K. Sharma
Summary: This study demonstrates the significant influence of the troponyl group on the structure and conformation of short peptides, confirmed through various experimental methods.
Article
Biochemistry & Molecular Biology
Giuliana Fusco, Francesco Bemporad, Fabrizio Chiti, Christopher M. M. Dobson, Alfonso De Simone
Summary: Understanding the differences in adaptation between proteins from hyperthermophilic organisms and their mesophilic homologues is crucial for unraveling the mechanisms of biological activity in proteins. Researchers measured NMR residual dipolar couplings and performed additional NMR experiments to study the structural and dynamical properties of a hyperthermophilic acylphosphatase enzyme and a human homologue. The results identified key differences in protein-protein and protein-ligand interactions, shedding light on the structure-dynamics-function relationship associated with the thermal adaptation strategies of protein molecules.
FRONTIERS IN MOLECULAR BIOSCIENCES
(2022)
Article
Chemistry, Multidisciplinary
Saikat Pahan, Sanjit Dey, Gijo George, Souvik Panda Mahapatra, DRGKoppalu R. Puneeth Kumar, Hosahudya. N. Gopi
Summary: In this study, chiral beta-double helices constructed from specific amino acids were observed in both single crystals and in solution. These structures can transport ions across membranes, suggesting their potential applications in designing functional foldamers.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Ya-Ming Tian, Evamaria Hofmann, Wagner Silva, Xiang Pu, Didier Touraud, Ruth M. M. Gschwind, Werner Kunz, Burkhard Koenig
Summary: The amino alcohol meglumine solubilizes organic compounds in water and enforces the formation of electron donor acceptor (EDA) complexes, resulting in unique cross-coupling reactions. UV-A photoinduced electron transfer within the EDA complexes leads to the cleavage of halide ions and recombination of arenes, followed by rearomatization and proton loss. UV and NMR measurements demonstrate the significance of the EDA aggregates for the photoinduced reaction. Enforced EDA aggregate formation in water provides new activation modes for organic photochemical synthesis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Alexander Reichle, Magdalena Koch, Hannes Sterzel, Lea-Joy Grosskopf, Johannes Floss, Julia Rehbein, Oliver Reiser
Summary: The visible light-mediated copper-catalyzed vicinal difunctionalization of olefins utilizing bromonitroalkanes as ATRA reagents is reported. This method offers high yields, fast reaction times, and environmentally benign reaction conditions with a wide scope, allowing rapid functionalization of activated and unactivated olefins. Additionally, it demonstrates the late-stage functionalization of biologically active molecules and the upscaling to gram quantities, providing possibilities for further transformations such as the preparation of nitro- and aminocyclopropanes. Moreover, this study highlights the unique role of copper in photoredox catalysis by stabilizing and interacting with radical intermediates in its coordination sphere, as revealed by EPR studies that show its superior performance compared to iridium-based photocatalysts.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Willibald J. Stockerl, Ruth M. Gschwind
Summary: This article describes the observation and assignment of high energetic (Z)-configured intermediates in imidazolidinone iminium ions through in situ photoisomerization. Stabilization conditions for (E,Z) and (Z,Z) isomers were also determined.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Organic
Nejc Petek, Helena Brodnik, Oliver Reiser, Bogdan Stefane
Summary: A Cu(I)-photoredox-catalyzed trifluoromethylchlorosulfonylation reaction of terminal alkynes under visible light conditions has been developed. The reaction yields trifluoromethyl-substituted vinylsulfonyl chlorides, which can subsequently be coupled to a second alkyne under photocatalytic conditions. The method shows high regio- and stereoselectivity and can be applied to aliphatic and aromatic alkynes with various functional groups, producing synthetically valuable intermediates.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Tanika Kessaratikoon, Tharinee Theerathanagorn, Daniel Crespy, Valerio D'Elia
Summary: The catalytic cycloaddition of CO2 to epoxides is a promising method for converting CO2 into value-added products. Metal-free organocatalytic compounds, which are inexpensive, nontoxic, and readily available, are attractive catalysts for this transformation. This review highlights recent advances in the development of polymer-based organocatalytic materials that meet the requirements of affordability and availability. The synthetic routes, monomers, and supports employed are considered, and the effects of chemical and structural features on catalytic performance are discussed.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Maximilian Franta, Johannes Gramueller, Philipp Dullinger, Simon Kaltenberger, Dominik Horinek, Ruth M. Gschwind
Summary: Chiral phosphoric acids (CPA) have been widely used as catalysts in organocatalysis, but the selection of the optimal catalyst is still a challenge. This study identified two reaction pathways with inverse stereoselectivities in the CPA-catalyzed transfer hydrogenation of imines, involving either a single CPA or a hydrogen bond bridged dimer as the active catalyst. Through NMR measurements and DFT calculations, it was revealed that the dimeric pathway had stronger substrate activation via cooperativity. The temperature and catalyst loading could be adjusted to favor either pathway and enhance the enantiomeric excess (ee) of the product. This research is expected to have a significant impact on the optimization and prediction of CPA catalysis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Engineering, Chemical
Sawarin Saengsaen, Silvano Del Gobbo, Valerio D'Elia
Summary: Nanomaterials based on SnO2 and ZnO were investigated as active and inexpensive catalysts for the cycloaddition of CO2 to epoxides. SnO2 nanoparticles were found to be the most active catalyst under mild reaction conditions and could tolerate impure CO2 feeds. This study shows the promise of SnO2 nanoparticles as a readily available and low-cost material for the production of cyclic carbonates under atmospheric CO2 pressure.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2023)
Article
Chemistry, Organic
Sebastian Fischer, Terrence-Thang H. Nguyen, Andreas Ratzenboeck, Huw M. L. Davies, Oliver Reiser
Summary: A stereoselective, solvent- and metal-free method for endocyclic C-C bond cleavage of monocyclopropanated cyclopentadienes mediated by strong acids has been developed. It leads to the formation of highly functionalized six-membered carbocycles with high stereocontrol. The critical step involves the formation of a cyclopropyl carbocation that undergoes endocyclic ring opening through an SN2'-type attack of various nucleophiles. Subsequent synthetic transformations demonstrate the versatility of the resulting cyclohexenes for the synthesis of compounds with nonconventional substitution patterns.
Article
Chemistry, Organic
Daniel Dobler, Michael Leitner, Peter Kreitmeier, Oliver Reiser
Summary: An atom-efficient method for synthesizing 2-pyrone on a multigram scale was developed using a large-scale thermal rearrangement of cyclopentadienone epoxide as the key step. This approach also provides easy access to 6-substituted 2-pyrone natural product derivatives.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Multidisciplinary
Tirtha Mandal, Narenderreddy Katta, Hendrik Paps, Oliver Reiser
Summary: This paper presents a sequential photocatalytic strategy that combines Cu(II)/Cu(I)-catalytic cycles for the oxoallylation of vinyl arenes using a-haloketones. Initially, Cu(II)-photocatalyzed oxohalogenation generates halide radicals from acyl halides, utilizing air as an oxidant, and can be used for late-stage modification of pharmaceuticals and agrochemicals. The subsequent one-pot Cu(I)-photocatalyzed allylation of a-bromoketones proceeds with high regio- and chemoselectivity, unaffected by the electronic nature of the styrenes.
ACS ORGANIC & INORGANIC AU
(2023)
Review
Chemistry, Multidisciplinary
Johannes Gramu''ller, Ruth M. Gschwind
Summary: The energetic contribution of London dispersion (LD) can cover a broad range in chemical catalysis, but there are still many obstacles and questions that remain. This Account describes the experimental exploration of LD in catalytic systems using NMR spectroscopy to dissect and quantify its contribution, and discusses the application of bulky substituents as dispersion energy donors (DEDs) in confined catalytic pockets. The findings highlight the importance of minimizing entropic contributions for LD to fully unfold its potential.
ACCOUNTS OF CHEMICAL RESEARCH
(2023)
Article
Chemistry, Physical
Krissada Norseeda, Prapussorn Yingcharoen, Phongprapan Nimnual, Sodsai Puchum, Sunatda Arayachukiat, Taradon Piromchart, Manfred Wagner, Hendrik Zipse, Valerio D'Elia
Summary: In this study, we discovered a cyclic carbonate-based compound with amphiphilic properties by combining epichlorohydrin carbonate and a long chain trialkylphosphine. Through NMR techniques, we investigated the composition and formation mechanism of the phosphonium salts formed in a single phase obtained through the reaction of these insoluble reagents. The obtained phase showed immiscibility with water and hydrocarbons and had intermediate density, making it a potential triphasic demulsifier for water in oil mixtures.
JOURNAL OF MOLECULAR STRUCTURE
(2023)
Article
Chemistry, Multidisciplinary
Tharinee Theerathanagorn, Anna Vidal-Lopez, Aleix Comas-Vives, Albert Poater, Valerio D'Elia
Summary: The study demonstrates that water-soluble organocatalysts can efficiently synthesize cyclic carbonates from CO2 and various epoxides in water-organic biphasic systems. The addition of simple inorganic salts accelerates the reaction rates and seawater is particularly effective as the aqueous layer. Control experiments and DFT calculations provide insights into the heterogeneous catalytic process at the interface between water droplets and the epoxide phase.
Article
Chemistry, Multidisciplinary
Alexander Reichle, Oliver Reiser
Summary: Photocatalysis has become a powerful strategy for selective functionalization of molecules through radical intermediates. While iridium or ruthenium-based photocatalysts have been well-studied, the use of earth-abundant metal-based photocatalysts is less explored. Recently, the concept of light-induced homolysis using earth-abundant 3d-metal complexes has gained significant interest despite their short excited-state lifetimes. Cu(ii)-complexes play a prominent role in this concept and recent developments in organic synthesis showcase the future prospects of this growing field.
Article
Nanoscience & Nanotechnology
Ounjit Sodpiban, Tanika Kessaratikoon, Jacob Smith, Guodong Ren, Silvano Del Gobbo, Sonali Das, Miaofang Chi, Valerio D'Elia, Bruce C. Gates
Summary: This study prepares atomically dispersed cerium catalysts to enhance their activity in CO oxidation reaction. By using Ce-(III) and Ce-(IV) precursors, the cerium catalysts on MgO support were successfully prepared and characterized before and after catalysis using various techniques. The results show that the excellent catalyst maintains stable activity during the 2-day reaction time and exhibits improved reducibility with the transformation of cerium ions.
ACS APPLIED MATERIALS & INTERFACES
(2023)
