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Peptide synthesis

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https://www.readbyqxmd.com/read/29148752/substituent-effects-on-the-reactivity-of-cyclic-tertiary-sulfamidates
#1
Claudio D Navo, Nuria Mazo, Alberto Avenoza, Jesús H Busto, Jesús M Peregrina, Gonzalo Jiménez-Osés
The reactivity of cyclic tertiary sulfamidates derived from α-methylisoserine strongly depends on the substitution at the C and N termini. These substrates are one of the very few examples able to undergo nucleophilic ring-opening at a quaternary carbon with complete inversion of the configuration, as demonstrated both experimentally and computationally. When the sulfonamide is unprotected, the characteristic ring-opening reaction is completely silenced, which explains that the majority of the ring-opening reactions reported in the literature invoke N-alkyl or N-acyl-protected sulfamidates...
November 17, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29148157/novel-ws9326a-derivatives-and-one-novel-annimycin-derivative-with-antimalarial-activity-are-produced-by-streptomyces-asterosporus-dsm-41452-and-its-mutant
#2
Andreas Bechthold, Songya Zhang, Jing Zhu, David Zechel, Claudia Jessen-Trefzer, Richard T Eastman, Thomas Paululat
In this study we report that Streptomyces asterosporus DSM 41452 is a producer of new molecules related to the non-ribosomal cyclodepsipeptide WS9326A and the polyketide Annimycin. S. asterosporus DSM 41452 is shown to produce six cyclodepsipeptides and peptides, WS9326A to G. Notably, the compounds WS9326F and WS9326G have not been de-scribed before. The genome of S. asterosporus DSM 41452 was sequenced and a putative WS9326A gene cluster was iden-tified. Gene deletion experiments confirmed that this cluster is responsible for the biosynthesis of WS9326A to G...
November 17, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29147502/chemical-space-guided-discovery-of-antimicrobial-bridged-bicyclic-peptides-against-pseudomonas-aeruginosa-and-its-biofilms
#3
Ivan Di Bonaventura, Xian Jin, Ricardo Visini, Daniel Probst, Sacha Javor, Bee-Ha Gan, Gaëlle Michaud, Antonino Natalello, Silvia Maria Doglia, Thilo Köhler, Christian van Delden, Achim Stocker, Tamis Darbre, Jean-Louis Reymond
Herein we report the discovery of antimicrobial bridged bicyclic peptides (AMBPs) active against Pseudomonas aeruginosa, a highly problematic Gram negative bacterium in the hospital environment. Two of these AMBPs show strong biofilm inhibition and dispersal activity and enhance the activity of polymyxin, currently a last resort antibiotic against which resistance is emerging. To discover our AMBPs we used the concept of chemical space, which is well known in the area of small molecule drug discovery, to define a small number of test compounds for synthesis and experimental evaluation...
October 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/29144748/chemical-modification-for-proteolytic-stabilization-of-the-selective-%C3%AE-v%C3%AE-3-integrin-rgdechi-peptide-in-vitro-and-in-vivo-activities-on-malignant-melanoma-cells
#4
Daniela Comegna, Antonella Zannetti, Annarita Del Gatto, Ivan de Paola, Luigi Russo, Sonia Di Gaetano, Annamaria Liguoro, Domenica Capasso, Michele Saviano, Laura Zaccaro
Herein we report the synthesis and biological characterization of the novel peptide ψRGDechi as the first step towards novel targeted theranostics in melanoma. This pseudo-peptide is designed from our previously reported RGDechi peptide, known to bind selectively αvβ3 integrin, and differs for a modified amide bond at the main protease cleavage site. This chemical modification drastically reduces the enzymatic degradation in serum, compared to its parental peptide, resulting in an overall magnification of the biological activity on a highly expressing αvβ3 human metastatic melanoma cell line...
November 16, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29143375/an-immunoinformatics-approach-to-define-t-cell-epitopes-from-polyketide-and-non-ribosomal-peptide-synthesis-proteins-of-mycobacterium-tuberculosis-as-potential-vaccine-candidates
#5
S Dhivya, V Baskar, S R Kumar, R Sathishkumar
The role of polyketide and non-ribosomal proteins from the class of small molecule metabolism of Mycobacterium tuberculosis is well documented in envelope organization, virulence, and pathogenesis. Consequently, the identification of T cell epitopes from these proteins could serve to define potential antigens for the development of vaccines. Fourty-one proteins from polyketide and non-ribosomal peptide synthesis of small molecule metabolism proteins of M tuberculosis H37Rv were analyzed computationally for the presence of HLA class I binding nanomeric peptides...
November 16, 2017: Journal of Molecular Recognition: JMR
https://www.readbyqxmd.com/read/29143364/automated-preparation-of-2-18-f-fluoropropionate-labelled-peptides-using-a-flexible-multi-stage-synthesis-platform-iphase-flexlab
#6
Mohammad B Haskali, Peter D Roselt, Rodney J Hicks, Craig A Hutton
Radiolabelled peptides are vital tools used in positron emission tomography (PET) imaging for the diagnosis of disease, drug discovery and biomedical research. Peptides are typically labelled through conjugation to a radiolabelled prosthetic group, which usually necessitates complex, multi-step procedures, especially for fluorine-18 labelled peptides. Herein, we describe the automated synthesis and formulation of 2-[(18) F]fluoropropionate labelled RGD-peptides through use of the iPHASE Flexlab as an effective dual-stage radiochemical synthesis module...
November 16, 2017: Journal of Labelled Compounds & Radiopharmaceuticals
https://www.readbyqxmd.com/read/29142995/screening-of-novel-rgd-peptides-to-modify-nanoparticles-for-targeted-cancer-therapy
#7
Liang Ge, Xinru You, Keqing Huang, Yang Kang, Yuejian Chen, Ying Zhu, Yuan Ren, Yuan Zhang, Jun Wu, Hai Qian
New targeted RGD peptides obtained by solid phase peptide synthesis (SPPS) were successfully screened by Molecular Operating Environment (MOE) and used for the building of the 6-O-carboxymethyl chitosan based carrier with an active target on the surface. CRGDYC-6-O-carboxymethyl chitosan based nanoparticles (NPs) loaded with doxorubicin hydrochloride (DOX) were successfully prepared by an ionic gelation method with the carrier synthesized before. Synthesis conditions and formulation parameters were optimized by determining the characteristics of nanoparticles including the particle size and drug encapsulation efficiency...
November 16, 2017: Biomaterials Science
https://www.readbyqxmd.com/read/29142468/glucagon-like-peptide-2-modulates-the-nitrergic-neurotransmission-in-strips-from-the-mouse-gastric-fundus
#8
Rachele Garella, Eglantina Idrizaj, Chiara Traini, Roberta Squecco, Maria Giuliana Vannucchi, Maria Caterina Baccari
AIM: To investigate whether glucagon-like peptide-2 (GLP-2) influences the neurally-induced responses in gastric strips from mice, since no data are available. METHODS: For functional experiments, gastric fundal strips were mounted in organ baths containing Krebs-Henseleit solution. Mechanical responses were recorded via force-displacement transducers, which were coupled to a polygraph for continuous recording of isometric tension. Electrical field stimulation (EFS) was applied via two platinum wire rings through which the preparation was threaded...
October 28, 2017: World Journal of Gastroenterology: WJG
https://www.readbyqxmd.com/read/29140694/tyrocidine-a-analogues-bearing-the-planar-d-phe-2-abz-turn-motif-how-conformation-impacts-bioactivity
#9
Alan J Cameron, Patrick J B Edwards, Elena Harjes, Vijayalekshmi Sarojini
The D-Phe-Pro β-turn of the cyclic β-hairpin antimicrobial decapeptide Tyrocidine A, (Tyrc A) was substituted with the D-Phe-2-aminobenzoic acid (2-Abz) motif in a synthetic analogue (1). NMR structure of 1 demonstrated that compound 1 retained the β-hairpin structure of Tyrc A with additional planarity, resulting in approx. 30-fold reduced haemolysis than Tyrc A. Although antibacterial activity was partially compromised, a single Gln to Lys substitution (2) restored activity equivalent to Tyrc A against S...
November 15, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29140480/the-intrinsically-disordered-n-terminal-arm-of-the-brome-mosaic-virus-coat-protein-specifically-recognizes-the-rna-motif-that-directs-the-initiation-of-viral-rna-replication
#10
Alexander Jacobs, Haley Hoover, Edward Smith, David E Clemmer, Chul-Hyun Kim, C Cheng Kao
In the brome mosaic virus (BMV) virion, the coat protein (CP) selectively contacts the RNA motifs that regulate translation and RNA replication (Hoover et al., 2016. J. Virol. 90, 7748). We hypothesize that the unstructured N-terminal arm (NTA) of the BMV CP can specifically recognize RNA motifs. Using ion mobility spectrometry-mass spectrometry, we demonstrate that peptides containing the NTA of the CP were found to preferentially bind to an RNA hairpin motif that directs the initiation of BMV RNA synthesis...
November 11, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/29139348/regulation-of-hepatitis-c-virus-replication-via-threonine-phosphorylation-of-the-ns5a-protein
#11
Niluka Goonawardane, Douglas Ross-Thriepland, Mark Harris
The hepatitis C virus non-structural 5A (NS5A) protein is highly phosphorylated and plays roles in both virus genome replication and assembly of infectious virus particles. NS5A comprises three domains separated by low complexity sequences (LCS). Mass spectrometry analysis of NS5A revealed the existence of a singly phosphorylated tryptic peptide corresponding to the end of LCS I and the beginning of domain II that contained a number of potential phosphorylatable residues (serines and threonines). Here we use a mutagenic approach to investigate the potential role of three of these threonine residues...
November 15, 2017: Journal of General Virology
https://www.readbyqxmd.com/read/29136364/rational-design-and-synthesis-of-post-functionalizable-peptide-foldamers-as-helical-templates
#12
Takashi Misawa, Yasunari Kanda, Yosuke Demizu
We herein developed post-functionalizable helical peptides composed of Leu, Aib, and Azl residues. We show that the synthesized peptides 1 and 2 form helical structures, and may be modified using specific side chain or several functional groups by the click reaction without influencing their secondary structures.
November 14, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/29135944/design-synthesis-and-use-of-peptides-derived-from-human-papillomavirus-l1-protein-for-the-modification-of-gold-electrode-surfaces-by-self-assembled-monolayers
#13
John Alejandro Lara Carrillo, Ricardo Fierro Medina, Juan Manríquez Rocha, Erika Bustos Bustos, Diego Sebastián Insuasty Cepeda, Javier Eduardo García Castañeda, Zuly Jenny Rivera Monroy
In order to obtain gold electrode surfaces modified with Human Papillomavirus L1 protein (HPV L1)-derived peptides, two sequences, SPINNTKPHEAR and YIK, were chosen. Both have been recognized by means of sera from patients infected with HPV. The molecules, Fc-Ahx-SPINNTKPHEAR, Ac-C-Ahx-(Fc)KSPINNTKPHEAR, Ac-C-Ahx-SPINNTKPHEAR(Fc)K, C-Ahx-SPINNTKPHEAR, and (YIK)₂-Ahx-C, were designed, synthesized, and characterized. Our results suggest that peptides derived from the SPINNTKPHEAR sequence, containing ferrocene and cysteine residues, are not stable and not adequate for electrode surface modification...
November 14, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29134764/peptides-derived-from-histidine-and-methionine-rich-regions-of-copper-transporter-1-exhibit-anti-angiogenic-property-by-chelating-extracellular-cu
#14
Iyer Gomathy Narayanan, K N Sulochana
Angiogenesis is a process of synthesis of new blood vessels from pre-existing vasculature. Copper (Cu) as a micronutrient is important to many proteins for their physiological roles. Cu is transported by ceruloplasmin from liver to other parts of the body. Copper transporter 1 (CTR1) is a transmembrane protein which participitate in Cu transport across the cell. It is also known to be involved in angiogenesis. In this study, we have designed three peptides from copper binding regions of CTR1 which are rich in histidine and methionine...
November 14, 2017: Chemical Biology & Drug Design
https://www.readbyqxmd.com/read/29133117/application-of-mixed-peptide-arrays-to-study-combinatorial-readout-of-chromatin-modifications
#15
Rebekka Mauser, Goran Kungulovski, David Meral, Daniel Maisch, Albert Jeltsch
The N-terminal tails of histone proteins are massively decorated with post-translational modifications (PTMs), which play important roles in the regulation of gene expression. Several highly conserved chromatin interacting proteins can bind to histone modifications in a sequence and modification specific manner employing specific reading domains. These proteins often contain several reading domains, which can cooperate in the readout of different PTMs. To gain a better insight into the combinatorial readout of PTMs, we developed a method to study the binding of double reading domains to mixed peptide arrays containing two different peptides in each spot...
November 10, 2017: Biochimie
https://www.readbyqxmd.com/read/29133052/design-and-synthesis-of-short-amphiphilic-cationic-peptidomimetics-based-on-biphenyl-backbone-as-antibacterial-agents
#16
Rajesh Kuppusamy, Muhammad Yasir, Thomas Berry, Charles G Cranfield, Shashidhar Nizalapur, Eugene Yee, Onder Kimyon, Aditi Taunk, Kitty K K Ho, Bruce Cornell, Mike Manefield, Mark Willcox, David StC Black, Naresh Kumar
Antimicrobial peptides (AMPs) and their synthetic mimics have received recent interest as new alternatives to traditional antibiotics in attempts to overcome the rise of antibiotic resistance in many microbes. AMPs are part of the natural defenses of most living organisms and they also have a unique mechanism of action against bacteria. Herein, a new series of short amphiphilic cationic peptidomimetics were synthesized by incorporating the 3'-amino-[1,1'-biphenyl]-3-carboxylic acid backbone to mimic the essential properties of natural AMPs...
November 10, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29133050/newly-designed-organotin-iv-carboxylates-with-peptide-linkage-synthesis-structural-elucidation-physicochemical-characterizations-and-pharmacological-investigations
#17
Muhammad Sirajuddin, Vickie McKee, Muhammad Tariq, Saqib Ali
Fourteen new organotin(IV) carboxylate complexes with peptide linkage of (2-(4-methoxy-2-nitrophenylcarbamoyl)benzoic acid) were successfully synthesized and characterized by elemental analyses, FT-IR, NMR ((1)H, (13)C and (119)Sn) and single crystal X-ray techniques. FT-IR results of the sodium salt of 2-(4-methoxy-2-nitrophenylcarbamoyl)benzoic acid and complexes showed that the coordination took place via oxygen atoms of the carboxylate group. (1)J((119)Sn-(13)C), (2)J((119)Sn-(1)H) and θ values calculated from (1)H and (13)C NMR data using Lockhart's equation reveal a trigonal bipyramidal geometry for triorganotin(IV) derivatives and an octahedral geometry for diorganotin(IV) derivatives...
November 4, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29131958/design-synthesis-and-biological-assessment-of-biased-allosteric-modulation-of-the-urotensin-ii-receptor-using-achiral-1-3-4-benzotriazepin-2-one-turn-mimics
#18
Antoine Douchez, Étienne Billard, Terence Hébert, David Chatenet, William D Lubell
Benzotriazepin-2-ones were designed to mimic the suggested bioactive γ-turn conformation of the Bip-Lys-Tyr tripeptide in Urocontrin ([Bip(4)]URP), which modulates the urotensin II receptor (UT) and differentiates the effects of the endogenous ligands urotensin II (UII) and urotensin II-related peptide (URP). Twenty-six benzotriazepin-2-ones were synthesized by acylation of anthranilate-derived amino ketones with an aza-glycine equivalent, chemoselective nitrogen functionalization and ring closure. Several mimics exhibited selective modulatory effects on hUII- and URP-associated vasoconstriction in an ex-vivo rat aortic ring bioassay...
November 13, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29131581/template-assisted-enzymatic-synthesis-of-oligopeptides-from-a-polylactide-chain
#19
Jenny Fagerland, Daniela Pappalardo, Björn Schmidt, Per-Olof Syrén, Anna Finne Wistrand
Peptides are often attached to polymer materials, as bioactive components, for the control of interactions between the material and its surrounding proteins and cells. However, synthesizing peptides and attaching them to polymers can be challenging and laborious. Herein, we describe the grafting of oligopeptides to an aliphatic polyester, using a one-step chemo-enzymatic synthesis with papain as the biocatalyst. To enable enzyme-mediated functionalization of the polyester, ethyl hept-6-enoylalaninate (grafter) was synthesized and attached to polylactide chains using thiol-ene click reactions...
November 13, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/29131552/activation-of-the-wnt-pathway-by-small-peptides-rational-design-synthesis-and-biological-evaluation
#20
Simone Brogi, Samuele Maramai, Margherita Brindisi, Giulia Chemi, Valentina Porcari, Claudio Corallo, Luigi Gennari, Ettore Novellino, Anna Ramunno, Stefania Butini, Giuseppe Campiani, Sandra Gemma
A computational analysis of the X-ray structure of the low-density lipoprotein receptor-related protein 6 (LRP6) with Dickkopf-1 (DKK1) C-terminal fragment has allowed us to rationally design a small set of decapeptides (1a-e). These compounds behave as agonists of the canonical Wnt pathway in the micromolar range when tested on a dual luciferase Wnt functional assay in glioblastoma cells. Lack of cellular toxicity was assessed for compounds 1c and 1d in human primary osteoblasts isolated from sponge bone tissue (femoral heads or knee of old patients)...
November 13, 2017: ChemMedChem
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