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Chembiochem: a European Journal of Chemical Biology

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https://www.readbyqxmd.com/read/30025196/direct-access-to-medium-chain-%C3%AE-%C3%AF-dicarboxylic-acids-using-a-baeyer-villiger-monooxygenase-of-abnormal-regioselectivity
#1
Jia-Mei Yu, Yuan-Yang Liu, Yu-Cong Zheng, Hao Li, Xiao-Yan Zhang, Gao-Wei Zheng, Chun-Xiu Li, Yunpeng Bai, Jian-He Xu
Baeyer-Villiger monooxygenases (BVMOs) are versatile biocatalysts in organic synthesis that can generate esters or lactones by inserting a single oxygen atom adjacent to a carbonyl moiety. Regioselectivity of BVMOs is essential in determining the ratio of two regioisomers for converting asymmetric ketones. Herein, we reported a novel BVMO from Pseudomonas aeruginosa (PaBVMO), and exploited it for the direct synthesis of medium-chain α,ω-dicarboxylic acids via a two-step chemo-enzymatic route. To our knowledge, PaBVMO displayed the highest abnormal regioselectivity toward a variety of long-chain aliphatic keto acids (C16-C20) to date, affording dicarboxylic monoesters with a ratio up to 95%...
July 19, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/30019804/blood-group-o-%C3%A2-a-transformation-by-chemical-ligation-of-erythrocytes
#2
Ivan Ryzhov, Alexander Tuzikov, Holly Perry, Elena Korchagina, Niсolai Bovin
Agglutination of red blood cells (RBCs) is routine and practically the only method for ABH typing in clinical practice. However, exact mechanistic details of agglutination are not yet thoroughly studied. In this research RBCs of blood group O were converted to blood group A using two approaches: by chemical ligation of the cells' glycocalyx with synthetic blood group A tetrasaccharide and by insertion of synthetic glycolipid carring the same A antigen in cell's membrane. Characteristics of agglutination with antibodies were comparable between O→A ligated and natural A RBCs...
July 18, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/30019519/photosensitised-multiheme-cytochromes-as-light-driven-molecular-wires-and-resistors
#3
Jessica van Wonderen, Daobo Li, Samuel Piper, Cheuk Lau, Leon Piper, Christopher Hall, Thomas Clarke, Nicholas Watmough, Julea N Butt
Multiheme cytochromes possess closely packed redox-active hemes arranged as chains spanning the tertiary structure. Here we describe five variants of a representative multiheme cytochrome engineered as biohybrid phototransducers converting light to electricity. Each variant possesses a single Cys-sulfhydryl near a terminus of the heme chain and that was efficiently labelled with a Ru(II)(bipyridine)3 photosensitiser. When irradiated in the presence of a sacrificial electron donor the proteins exhibited different behaviours...
July 18, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/30019476/recent-advances-in-the-design-of-targeted-iridium-iii-photosensitizers-for-photodynamic-therapy
#4
REVIEW
Huaiyi Huang, Samya Banerjee, Peter J Sadler
Photodynamic therapy (PDT) is a noninvasive treatment for certain types of cancer, bacterial, fungal and viral infections, and skin diseases. In recent years, adaptation of this treatment so as to achieve more specific targeted cancer therapy in particular has attracted significant attention. We focus herein on the design of novel iridium-based photosensitizers (PSs) with tunable photophysical and photobiological properties as efficient PDT agents. We highlight the ability of some IrIII photosensitizers to target specific cellular components, including their activation by one- and two-photon irradiation...
July 18, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/30007003/three-s-s-for-aptamer-mediated-control-of-dna-nanostructure-dynamics-shape-self-complementarity-and-spatial-flexibility
#5
Simon Chi-Chin Shiu, Andrew Brian Kinghorn, Yusuke Sakai, Yee-Wai Cheung, Jonathan Gardiner Heddle, Julian Alexander Tanner
DNA aptamers are ideal tools to enable modular control of DNA nanostructure dynamics. For molecular recognition they have a particular advantage compared to antibodies, namely they can be integrated into DNA nanostructures in a bespoke manner by base-pairing or nucleotide extension without any complex bioconjugation strategy. Such simplicity will be critical when considering advanced therapeutic and diagnostic applications of DNA nanostructures. However, optimizing DNA aptamers for functional control of DNA nanostructure dynamics can be challenging...
July 14, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29999233/the-photosensitizing-clinical-agent-verteporfin-is-an-inhibitor-of-spak-and-osr1-kinases
#6
Mubarak A AlAmri, Hachemi Kadri, Mark Jeeves, Luke J Alderwick, Youcef Mehellou
SPAK and OSR1 are two serine/threonine protein kinases that play important key roles in regulating ion homeostasis. Various SPAK and OSR1 mouse models exhibited reduced blood pressure. Herein, we report the discovery of Verteporfin, a photosensitizing agent used in photodynamic therapy, as a potent inhibitor of SPAK and OSR1 kinases. We show that Verteporfin binds the kinase domains of SPAK and OSR1 and inhibit their catalytic activity in an ATP-independent manner. In cells, Verteporfin was able to suppress the phosphorylation of the ion co-transporter NKCC1, a downstream physiological substrate of SPAK and OSR1 kinases...
July 12, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29992710/mechanism-of-braf-activation-through-biochemical-characterization-of-the-recombinant-full-length-protein
#7
Nicholas Cope, Christine Candelora, Kenneth Wong, Sujeet Kumar, Haihan Nan, Michael Grasso, Borna Novak, Yana Li, Ronen Marmorstein, Zhihong Wang
BRAF kinase plays an important role in mitogen activated protein kinase (MAPK) signaling and harbors activating mutations in about half of melanomas and in a smaller percentage in many other cancers. Despite its importance, few in vitro studies have been performed to characterize the biochemical properties of full-length BRAF. Here we describe a strategy to generate an active, intact form of BRAF protein suitable for in vitro enzyme kinetics. We show that purified intact BRAF protein auto-phosphorylates its kinase activation loop and this can be enhanced by binding its MEK protein substrate through an allosteric mechanism...
July 10, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29989277/an-in-vitro-selected-dnazyme-mutant-highly-specific-for-na-in-slightly-acidic-conditions
#8
Lingzi Ma, Juewen Liu
Sodium is one of the most ubiquitous metal ions in biology, while its DNA-based probes were reported only recently. A Na+-specific RNA-cleaving DNAzyme named NaA43 is active with Na+ alone. In this work, we used Co(NH3)63+ as the intended metal cofactor for in vitro selection, but obtained a mutant of the NaA43 DNAzyme. The mutant was named NaH1, which differs from NaA43 by only two nucleotides. NaA43 has an optimal of pH 7.0, while the optimal pH for NaH1 is 6.0. This difference might be due to our selection being performed at pH 6...
July 10, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29985553/flexible-assembly-of-cascade-enzyme-on-dna-triangle-prism-nanostructure-for-controlled-biomimetic-generation-of-nitric-oxide
#9
Li Zhou, Yu Liu, Hui Shi, Xiaohai Yang, Jin Huang, Songyang Liu, Qiaoshu Chen, Jianbo Liu, Kemin Wang
Spatial organization of multienzyme at specific positions for controlled reaction cascade has attracted wide attentions. Here, we report the construction of a biomimetic enzyme cascade organizing on DNA triangle prism (TP) nanostructures, which enabled efficient catalytical production of nitric oxide (NO) on a single microbead. Two enzymes, glucose oxidase (GOx) and horseradish peroxidase (HRP), were assembled at adjacent locations on DNA TP nanostructure by using DNA-binding protein adaptors with small interenzyme distances...
July 9, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29984452/antibody-bactericidal-macrocyclic-peptide-conjugates-to-target-gram-negative-bacteria
#10
Faycal Touti, Guillaume Lautrette, Ken Johnson, Jim Delaney, Andrew Wollacott, Hamid Tissire, Karthik Viswanathan, Zachary Shriver, Surin Mong, Alexander Mijalis, Obadiah Plante, Bradley Pentelute
To combat antimicrobial infections, new active molecules are needed. Antimicrobial peptides, ever abundant in nature, are a fertile starting point to develop new antimicrobial agents but suffer from low stability, low specificity and off-target toxicity. These drawbacks have limited their development. To overcome some of these limitations, we developed antibody-bactericidal macrocyclic peptide conjugates (ABCs) where the antibody directs the bioactive macrocyclic peptide to the targeted Gram-negative bacteria...
July 8, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29981252/protein-engineering-of-the-progesterone-hydroxylating-p450-monooxygenase-cyp17a1-alters-its-regioselectivity
#11
Lisa Morlock, Sascha Grobe, Kathleen Balke, Stephan Mauersberger, Dominique Böttcher, Uwe Bornscheuer
The CYP171 enzyme is known to catalyse a key step in the steroidogenesis of mammals. The substrates progesterone and pregnenolone are first hydroxylated at the C17 position, followed by the cleavage of the C17-C20 bond, yielding important precursors for glucosteroids and androgens. In this study, we focused on the reaction of the bovine CYP17A1 enzyme with progesterone as substrate. On the basis of a created homology model, active-site residues were identified and, systematically mutated to alanine. In whole-cell biotransformations, the importance of the residues N202, R239, G297, and E305 for substrate conversion was confirmed...
July 7, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29979493/azide-and-alkyne-bearing-metabolic-chemical-reporters-of-glycosylation-show-structure-dependent-feedback-inhibition-of-the-hexosamine-biosynthetic-pathway
#12
Lisa A Walter, Anna R Batt, Narek Darabedian, Balyn W Zaro, Matthew Robert Pratt
Metabolic chemical reporters (MCRs) of protein glycosylation are analogs of natural monosaccharides that bear reactive groups, like azides and alkynes. Upon treatment of living cells and organisms, these small molecules are biosynthetically transformed into nucleotide donor-sugars and then utilized by glycosyltransferases for the modification of proteins. Subsequent installation of tags using bioorthogonal chemistries can then enable the visualization and enrichment of these glycoproteins. While this two-step procedure is powerful, the utilization of MCRs has the potential to change the endogenous production of the natural repertoire of donor sugars...
July 6, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29974647/dna-binding-properties-of-new-fluorescent-azahx-amides-methoxy-pyridyl-aza-benzimidazole-pyrrole-imidazole-pyrrole
#13
Beibei Liu, Luke Pett, Konstantinos Kiakos, Pravin C Patil, Vijay Satam, John A Hartley, Moses Lee, W David Wilson
DNA minor groove binding polyamides have been extensively developed to control abnormal gene expression. Establishment of the novel, inherently fluorescent Hx-amides has provided an alternative path for studying DNA binding in cells by direct observation of cell localization. Because of the 2:1 antiparallel stacking homodimer binding mode of these molecules to DNA, modification of Hx-amides to AzaHx-amides has successfully extended the DNA recognition repertoire, from central CG (recognized by Hx-I) to central GC (recognized by AzaHx-P) recognition...
July 4, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29974638/biosynthetic-gene-cluster-of-a-d-tryptophan-containing-lasso-peptide-ms-271
#14
Zhi Feng, Yasushi Ogasawara, Satoshi Nomura, Tohru Dairi
MS-271, produced by Streptomyces sp. M-271, is a lasso peptide natural product comprising 21 amino acid residues with a D-tryptophan (D-Trp) at its C-terminus. Because lasso peptides are ribosomal peptides, the biosynthesis of MS-271, especially the mechanism of D-Trp introduction, is of great interest. The MS-271 biosynthetic gene cluster was identified by draft genome sequencing of the MS-271 producer and it was revealed that the precursor peptide contains all 21 amino acid residues including the C-terminal tryptophan...
July 4, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29969169/kinetically-stable-bicelle-with-dilution-tolerance-size-tunability-and-thermoresponsiveness-for-drug-delivery-applications
#15
Noriyuko Uchida, Noriko Nishizawa Horimoto, Kuniyo Yamada, Takaaki Hikima, Yasuhiro Ishida
Mixtures of a phospholipid (1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine: DPPC) and a sodium cholate-derived surfactant (SC-C5) at room temperature formed phospholipid bilayer fragments that were edge-stabilized by SC-C5 so-called bicelles. Because the bilayer melting point of DPPC (41 °C) is above room temperature and because SC-C5 has an exceptionally low critical micelle concentration (<0.5 mM), the bicelles are kinetically frozen at room temperature. Consequently, they exist even when the mixture is diluted to a concentration of 0...
July 3, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29968955/characterisation-of-the-carboxypeptidase-g2-catalytic-site-and-design-of-new-inhibitors-for-cancer-therapy
#16
Dhadchayini Jeyaharan, Carla Brackstone, James Schouten, Paul Davis, Ann M Dixon
The enzyme carboxypeptidase G2 (CPG2) is utilized in antibody directed enzyme pro-drug therapy (ADEPT) to catalyze the formation of an active drug from an inert pro-drug. Free CPG2 in the bloodstream must be inhibited before administration of the pro-drug in order to avoid a systemic reaction in the patient. Although a few small-molecule CPG2 inhibitors have been reported, none have been taken forward thus far. This lack of progress is due in part to a lack of structural understanding of the CPG2 active site as well as the absence of small molecules that can block the active site whilst targeting the complex for clearance...
July 3, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29968274/dna-primer-extension-with-cyclopropenylated-7-deaza-2-deoxyadenosine-and-efficient-bioorthogonal-labeling-in-vitro-and-in-living-cells
#17
Damian Damian Ploschik, Franziska Rönicke, Hanna Beike, Ralf Strasser, Hans-Achim Wagenknecht
A dATP analog for DNA labeling was synthesized with the 1-methylcylopropene (1MCP) group at the 7-position of 7-deaza-2'-deoxyadenosine, and applied for primer extension experiments. The real-time kinetic data reveals that this 1MCP-modified dATP analog is much faster incorporated into DNA than the similarly 1MCP-modified dUTP analog. The postsynthetic fluorescent labeling of these oligonucleotides works efficient according to PAGE analysis, and can be applied for immobilization of a functional antibody on a surface...
July 3, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29966048/enzymatic-fluorination-of-biotin-and-tetrazine-conjugates-for-pre-targeting-approaches-to-pet-imaging
#18
Phillip T Lowe, Sergio Dall'Angelo, Andrew Devine, Matteo Zanda, David O'Hagan
The use of radiolabelled antibodies and antibody-derived recombinant constructs have shown promise for both imaging and therapeutic use. In this context, the biotin-avidin/streptavidin pairing along with the inverse electron demand Diels-Alder reaction (IEDDA) have found application in pre-targeting approaches for positron emission tomography (PET). This study reports the fluorinase enzyme mediated transhalogenation (ClDA substrates to FDA products) of two antibody pre-targetting tools, a FDA-PEG-tetrazine and a [18F]FDA-PEG-biotin and each is assessed for their compatibility towards IEDDA ligation to trans-cyclooctene or affinity to avidin...
July 2, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29959812/a-possible-path-to-prebiotic-peptides-involving-silica-and-hydroxy-acid-mediated-amide-bond-formation
#19
Aaron D McKee, Thomas Michael Orlando, Nicholas V Hud, Christopher Bennett, Andrew K Saydjari, Martin Solano
Formation of alanine and glycine oligomers in films produced by drying aqueous mixtures of lactic acid and silica nanoparticles have been studied under plausible prebiotic conditions. The addition of silica results in alanine or glycine enrichment in the polymers. Oligomerization proceeds via ester-mediated peptide bond formation in an acidic and evaporative environment at temperatures as low as 85 °C. For both amino acids, the dominant species produced in the presence of silica and lactic acid are rich in amide bonds and ester deficient...
June 29, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29953718/super-resolution-imaging-of-amyloid-structures-over-extended-times-using-transient-binding-of-single-thioflavin-t-molecules
#20
Kevin Spehar, Tianben Ding, Yuanzi Sun, Niraja Kedia, Jin Lu, George R Nahass, Matthew D Lew, Jan Bieschke
Oligomeric amyloid structures are crucial therapeutic targets in Alzheimer's and other amyloid diseases. However, these oligomers are too small to be resolved by standard light microscopy. We have developed a simple and versatile tool to image amyloid structures using Thioflavin T without the need for covalent labeling or immunostaining. Dynamic binding of single dye molecules generates photon bursts that are used for fluorophore localization on a nanometer scale. Thus, photobleaching cannot degrade image quality, allowing for extended observation times...
June 28, 2018: Chembiochem: a European Journal of Chemical Biology
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