journal
MENU ▼
Read by QxMD icon Read
search

Chembiochem: a European Journal of Chemical Biology

journal
https://www.readbyqxmd.com/read/28107587/p450-bm3-catalyzed-regio-and-stereoselective-hydroxylation-aiming-at-the-synthesis-of-phthalides-and-isocoumarins
#1
Claudia Holec, Ute Hartrampf, Katharina Neufeld, Joerg Pietruszka
Cytochrome P450 BM3 monooxygenases are able to catalyze the regio- and stereoselective oxygenation of a broad range of substrates with promising potential for synthetic applications. To study the ability of P450 BM3 variants for the stereoselective benzylic hydroxylation of 2-alkylated benzoic acid esters, the biotransformation of methyl 2-ethylbenzoate was investigated resulting in both enantiomeric forms of 3-methylphthalide. In case of methyl 2-propylbenzoate as a substrate the regioselectivity of the reaction was shifted towards -hydroxylation resulting in the synthesis of enantioenriched (R)- and (S)-configured 3-methylisochroman-1-one...
January 20, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28107586/revealing-additional-stereocomplementary-pairs-of-old-yellow-enzymes-by-rational-transfer-of-engineered-residues
#2
Nathalie Nett, Sabine Duewel, Alexandra Annelis Richter, Sabrina Hoebenreich
Every year numerous protein engineering and directed evolution studies are published, increasing the knowledge which could be used by protein engineers. Here we test a protein engineering strategy that allows quick access to improved biocatalysts with very little screening effort. Conceptually it is assumed that engineered residues, previously identified by rational and random methods, induce similar improvements when transferred to family members. Applied to ene-reductases from the Old Yellow Enzyme family (OYE), the newly created variants were tested with three compounds revealing more stereocomplementary OYE pairs with potent turnover frequencies (up to 660 h-1) and excellent stereoselectivities (up to >99%)...
January 20, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28106939/maximizing-output-in-rna-programmed-peptidyl-transfer-reactions
#3
Margherita Di Pisa, Anett Hauser, Oliver Seitz
A chemical reaction that is triggered by specific RNA molecules may provide opportunities for the design of artificial feedback loops. We envision a peptidyl transfer reaction, in which mRNA encoding for antiapoptotic protein would instruct the synthesis of apoptosis-inducing peptides. In this study, we tackled the RNA-programmed synthesis of a 16mer peptide derived from the Bak-BH3 protein which inhibits the antiapoptotic protein Bcl-xL. The reaction involves the transfer of a thioester-linked donor peptide fragment from one PNA conjugate onto an acceptor peptide-PNA conjugate...
January 20, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28106332/copper-ii-controlled-molecular-glue-for-mismatched-dna
#4
Naoko Kotera, Régis Guillot, Marie-Paule Teulade-Fichou, Anton Granzhan
Isothermal hybridization of two DNA strands bearing three thymine-thymine (T-T) mismatches can be brought about in the presence of a stoichiometric amount of a bis-naphthalene macrocycle, 2,7-BisNP-NH. This process can be reverted by addition of a Cu(II) salt due to formation of a dinuclear metal complex which does not bind to DNA. Subsequent sequestration of Cu(II) releases the macrocycle and restores the hybridization state of DNA strands, thus allowing implementation of a fast fluorescent two-state DNA switch...
January 20, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28106328/on-the-influence-of-the-protonation-states-of-active-site-residues-on-ache-reactivation-a-qm-mm-approach
#5
Thomas Driant, Florian Nachon, Cyril Ollivier, Pierre-Yves Renard, Etienne Derat
Acetylcholinesterase (AChE) is an enzyme of the serine hydrolase superfamily and a mediator of the signal transmission at cholinergic synapses catalysing acetylcholine cleavage into an acetate and a choline. This enzyme is vulnerable to covalent inhibition by organophosphate compounds (like VX). The covalent inhibition of AChE does not revert spontaneously and in order to restore catalytic activity known reactivator compounds have limited action. Simulations of VX-inhibited AChE reactivation by pralidoxime, a classical reactivator, were performed by QM/MM...
January 19, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28103392/a-peroxygenase-from-chaetomium-globosum-catalyzes-the-selective-oxygenation-of-testosterone
#6
Jan Kiebist, Kai-Uwe Schmidtke, Jörg Zimmermann, Harald Kellner, Nico Jehmlich, René Ullrich, Daniel Zänder, Martin Hofrichter, Katrin Scheibner
Unspecific peroxygenases (UPO, EC 1.11.2.1) secreted by fungi open an efficient way to selectively oxyfunctionalize diverse organic substrates including less activated hydrocarbons by transferring peroxide-borne oxygen. Herein, we investigated a cell-free approach to incorporate epoxy and hydroxyl functionalities directly into the bulky molecule of testosterone by a novel unspecific peroxygenase that was produced by the ascomycetous fungus Chaetomium globosum in a complex medium rich in carbon and nitrogen...
January 19, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28098422/structural-elucidation-of-a-non-peptidic-inhibitor-specific-for-the-human-immunoproteasome
#7
Haissi Cui, Regina Baur, Camille Le Chapelain, Christian Dubiella, Wolfgang Heinemeyer, Eva Maria Huber, Michael Groll
Selective inhibition of the immunoproteasome is a promising approach towards the development of immunomodulatory drugs. Recently, a class of substituted thiazole compounds that combine a non-peptidic scaffold with the absence of an electrophile has been reported in a patent. Herein, we describe the mode of action of the lead compound using a sophisticated chimeric yeast model of the human immunoproteasome for structural studies. The inhibitor adopts a unique orientation perpendicular to the β5i substrate binding channel...
January 18, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28098416/motuporamine-derivatives-as-antimicrobial-agents-and-antibiotic-enhancers-against-resistant-gram-negative-bacteria
#8
Diane Borselli, Marine Blanchet, Jean-Michel Bolla, Aaron Muth, Kristen Skruber, Otto Phanstiel, Jean Michel Brunel
Dihydromotuporamine C and its derivatives were evaluated for their in vitro antimicrobial activities and antibiotic enhancement properties against Gram-negative bacteria and clinical isolates. The mechanism of action of one of these derivatives, MOTU-N44, was investigated against Enterobacter aerogenes by using fluorescent dyes to evaluate outer-membrane depolarization and permeabilization. Its efficiency correlated with inhibition of dye transport, thus suggesting that these molecules inhibit drug transporters by de-energization of the efflux pump rather than by direct interaction of the molecule with the pump...
January 18, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28094462/orientation-of-the-ompf-porin-in-planar-lipid-bilayers
#9
Sandra Antonia Ionescu, Sejeong Lee, Nicholas Housden, Renata Kaminska, Colin Kleanthous, Hagan Bayley
Outer membrane protein F (OmpF) is an abundant trimeric general diffusion porin that plays a central role in the transport of antibiotics and colicins across the outer membrane of E. coli. Individual OmpF trimers in planar lipid bilayers (PLB) show one of two current-voltage asymmetries, implying that insertion occurs with either the periplasmic or the extracellular end first. A method for establishing the orientation of OmpF in PLB was developed based on the targeted covalent modification, with membrane-impermeant reagents, of peripheral cysteine residues introduced near the periplasmic or the extracellular entrance...
January 17, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28093840/a-unique-genetically-encoded-fret-pair-in-mammalian-cells
#10
Amanda L Mitchell, Partha Sarathi Addy, Melissa A Chin, Abhishek Chatterjee
Förster resonance energy transfer (FRET) between two suitable fluorophores is a powerful tool to monitor dynamic changes in protein structure in vitro and in vivo. The ability to genetically encode a FRET pair represents a convenient "labeling-free" strategy to incorporate them into target protein(s). Currently, the only genetically encoded FRET pairs available for use in mammalian cells use fluorescent proteins. However, their large size can lead to unfavorable perturbations, particularly when two of them are used at the same time...
January 17, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28090736/rna-protection-is-effectively-achieved-by-pullulan-film-formation
#11
Yingfu Li, Ping-Yao Hsieh, Monsur Ali, Kha Tram, Sana Jahanshahi-Anbuhi, Christine Brown, John Brennan, Carlos Filipe
RNA is a functionally versatile polymer but suffers from susceptibility to spontaneous or RNase-catalyzed degradation. This vulnerability makes it difficult to preserve RNA for extended periods of time, which limits its use in various contexts, including practical applications of functional nucleic acids. Here we present a simple method to preserve RNA by pullulan (a complex sugar produced by Aureobasidium pullulans fungus) film formation. This strategy can markedly suppress both spontaneous and RNase-promoted degradation...
January 15, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28087991/an-exceptionally-selective-dna-cooperatively-binding-two-ca2-ions
#12
Wenhu Zhou, Runjhun Saran, Po-Jung Jimmy Huang, Jinsong Ding, Juewen Liu
Ca2+ is a highly important metal ion in biology and in the environment, leading to extensive work in developing sensors for Ca2+ detection. While many Ca2+ binding proteins are known, few nucleic acids can selectively bind Ca2+. DNA-based biosensors are attractive for its high stability and excellent programmability. Herein, we report a RNA-cleaving DNAzyme named EtNa cooperatively binding two Ca2+ ions but only one Mg2+. Four DNAzymes with known Ca2+-dependent activity were compared, and the EtNa has the best selectivity...
January 14, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28076665/carbohydrate-lectin-interactions-an-unexpected-contribution-to-affinity
#13
Giulio Navarra, Pascal Zihlmann, Roman P Jakob, Katia Stangier, Roland C Preston, Said Rabbani, Martin Smiesko, Bea Wagner, Timm Maier, Beat Ernst
Uropathogenic E. coli exploit the PapG-II adhesin for infecting host cells of the kidney; moreover, the expression of PapG-II located at the tip of bacterial pili has been correlated with the onset of pyelonephritis in humans, a potentially life-threatening condition. It was envisaged that the blocking of PapG-II, and thus bacterial adhesion, embodies a viable therapeutic alternative to conventional antibiotic treatment. Within our search for potent PapG-II antagonists, we observed an increase in affinity when tetrasaccharide 1, the natural ligand of PapG-II in human kidneys, was elongated to hexasaccharide 2, although the additional Siaα(2-3)Gal extension is not in direct contact with the lectin...
January 11, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28075512/alkyl-formate-ester-synthesis-by-a-fungal-baeyer-villiger-monooxygenase
#14
Felix Martin Ferroni, Carmien Tolmie, Martha Sophia Smit, Diederik Johannes Opperman
Baeyer-Villiger monooxygenase (BVMO) mediated synthesis of alkyl formate esters, important flavour and fragrance products, was investigated. A recombinant fungal BVMO from Aspergillus flavus was found to transform a selection of aliphatic aldehydes to alkyl formates with high regioselectivity. Near complete conversion of 10 mM octanal was achieved within 8 h with a regiomeric excess of ~80%. Substrate concentration was found to affect specific activity and regioselectivity of the BVMO as well as the rate of product autohydrolysis to the primary alcohol...
January 11, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28075053/synthesis-characterization-and-immunological-evaluation-of-self-adjuvanting-group-a-streptococcal-vaccine-candidates-bearing-various-lipidic-adjuvanting-moieties
#15
Vincent Fagan, Waleed M Hussein, Mei Su, Ashwini K Gidda, Michael R Batzloff, Michael F Good, Istvan Toth, Pavla Simerska
Four group A streptococcal glyco-lipopeptide vaccine candidates were prepared and characterized, each possessing different lipidic adjuvanting moieties. The immunogenicity of the compounds was evaluated by macrophage and dendritic cell uptake studies and by in vivo quantification of systemic IgG antibody using ELISA. Three of the four vaccine candidates showed a significant induction of IgG response compared to a negative control.
January 11, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28074539/ritterostatin-gn1n-a-cephalostatin-ritterazine-bis-steroidal-pyrazine-hybrid-selectively-targets-grp78
#16
Andrew J Ambrose, Evelyne A Santos, Paula C Jimenez, Danilo D Rocha, Diego V Wilke, Paolo Beuzer, Josh Axelrod, Ananda Kumar Kanduluru, Philip L Fuchs, Hu Cang, Letícia V Costa-Lotufo, Eli Chapman, James J La Clair
Natural products discovered using agnostic approaches, unlike rationally designed or HTS obtained leads, offer the ability to reveal new biological pathways, and hence, serve as an important vehicle to unveil new avenues in drug discovery. The ritterazine-cephalostatin family of natural products displays robust and potent anti-tumor activities, with sub-nanomolar growth inhibition against multiple cell lines and potent activity in xenograft models. Herein, we use comparative cellular and molecular biological methods to uncover the ritterazine/cephalostatin mode of cytotoxic action (MOA) in human tumor cells...
January 10, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28070925/bioorthogonal-fluorescent-labelling-of-biopolymers-via-inverse-electron-demand-diels-alder-reactions
#17
Eszter Kozma, Orsolya Demeter, Péter Kele
Inverse electron demand Diels-Alder (IEDDA) based biorthogonal labelling schemes have attracted much attention lately in chemical biology. The appealing features of this reaction such as the fast reaction kinetics, fully biorthogonal nature, and high selectivity helped chemical biologists to get deeper understanding of biochemical processes at the molecular level. By listing the components and debating the possibilities and limitations that lay behind these reagents we provide a recent snapshot of IEDDA-based biomolecular manipulation field with special focus on fluorescent modulation schemes through bioorthogonalized building blocks...
January 10, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28068458/synthetic-muc1-glycopeptide-bearing-%C3%AE-galnac-thr-as-tn-antigen-isomer-induces-antibodies-production-against-tumor-cells
#18
Vanessa Leiria Campo, Thalita Riul, Leandro Bortot, Maristela Martins-Teixeira, Marcelo Marchiori, Emanuela Iaccarino, Menotti Ruvo, Marcelo Dias-Baruffi, Ivone Carvalho
This study presents the synthesis of the novel protected O-glycosyl amino acids βGalNAc-SerOBn (1) and βGalNAc-ThrOBn (2) as mimetics of the natural Tn antigen (αGalNAc-Ser/Thr), along with the solid-phase assembly of the glycopeptides NHAcSer-Ala-Pro-Asp-Thr[αGalNAc]-Arg-Pro-Ala-Pro-Gly-BSA (3-BSA) and NHAcSer-Ala-Pro-Asp-Thr[βGalNAc]-Arg-Pro-Ala-Pro-Gly-BSA (4-BSA), bearing αGalNAc-Thr or βGalNAc-Thr, as mimetics of MUC1 tumor mucin glycoproteins. According to ELISA tests, mice immunizations with βGalNAc-glycopeptide 4-BSA induced higher sera titers (1:320000) if compared to immunizations with αGalNAc-glycopeptide 3-BSA (1:40000)...
January 9, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28067448/oled-loki-as-a-catalyst-for-tertiary-amine-and-hydroxamate-glycosylation
#19
Ryan R Hughes, Khaled A Shaaban, Jianjun Zhang, Hongnan Cao, George N Phillips, Jon S Thorson
We describe the ability of an engineered glycosyltransferase (OleD Loki) to catalyze the N-glycosylation of tertiary-amine-containing drugs and trichostatin hydroxamate glycosyl ester formation. As such, this study highlights the first bacterial model catalyst for tertiary-amine N-glycosylation and further expands the substrate scope and synthetic potential of engineered OleDs. In addition, this work could open the door to the discovery of similar capabilities among other permissive bacterial glycosyltransferases...
January 9, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28067438/chemoselective-reactions-for-the-synthesis-of-glycoconjugates-from-unprotected-carbohydrates
#20
Klaus Villadsen, Manuel C Martos-Maldonado, Knud J Jensen, Mikkel Boas Thygesen
Glycobiology is the comprehensive biological investigation of carbohydrates. The study of the role and function of complex carbohydrates often requires the attachment of carbohydrates to surfaces, their tagging with fluorophores, or conversion into natural or non-natural glycoconjugates, such as glycopeptides or -lipids. Glycobiology and its 'omics', glycomics, require easy and robust chemical methods for the construction of these glycoconjugates. This review gives an overview of the rapidly expanding field of chemical reactions that selectively convert unprotected carbohydrates into glycoconjugates through the anomeric position...
January 9, 2017: Chembiochem: a European Journal of Chemical Biology
journal
journal
34945
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"