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Pentapeptide

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https://www.readbyqxmd.com/read/28445034/dual-in-tether-chiral-centers-modulate-peptide-helicity
#1
Kuan Hu, Chengjie Sun, Mengying Yu, Wenjun Li, Huacan Lin, Jialin Guo, Yixiang Jiang, Chengxiang Lei, Zigang Li
The facile chemical modification on the peptide cross-linking moiety is an important strategy to improve the physico-chemical properties of a peptide. Herein, peptides were contrained into helical conformations using a dual in-tether chiral center strategy that induced synergistic effects between two chiral centers. A pentapeptide minimalistic model was used to determine a correlation between the absolute configurations of the dual in-tether chiral centers and the secondary structures of the peptides. This strategy provides an on-tether modification site that does not interrupt the secondary structure of the peptide...
April 26, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28435840/microbial-flora-probiotics-bacillus-subtilis-and-the-search-for-a-long-and-healthy-human-longevity
#2
COMMENT
Facundo Rodriguez Ayala, Carlos Bauman, Sebastián Cogliati, Cecilia Leñini, Marco Bartolini, Roberto Grau
Probiotics are live microorganisms that have beneficial effects on host health, including extended lifespan, when they are administered or present in adequate quantities. However, the mechanisms by which probiotics stimulate host longevity remain unclear and very poorly understood. In a recent study (Nat. Commun. 8, 14332 (2017) doi: 10.1038/ncomms14332), we used the spore-forming probiotic bacterium Bacillus subtilis and the model organism Caenorhabditis elegans to study the mechanism by which a probiotic bacterium affects host longevity...
March 16, 2017: Microbial Cell
https://www.readbyqxmd.com/read/28435448/inhibition-of-platelet-function-using-liposomal-nanoparticles-blocks-tumor-metastasis
#3
Yinlong Zhang, Jingyan Wei, Shaoli Liu, Jing Wang, Xuexiang Han, Hao Qin, Jiayan Lang, Keman Cheng, Yiye Li, Yingqiu Qi, Greg J Anderson, Saraswati Sukumar, Suping Li, Guangjun Nie
Extensive evidence has shown that platelets support tumor metastatic progression by inducing epithelial-mesenchymal transition of cancer cells and by shielding circulating tumor cells from immune-mediated elimination. Therefore, blocking platelet function represents a potential new avenue for therapy focused on eliminating metastasis. Here we show that liposomal nanoparticles bearing the tumor-homing pentapeptide CREKA (Cys-Arg-Glu-Lys-Ala) can deliver a platelet inhibitor, ticagrelor, into tumor tissues to specifically inhibit tumor-associated platelets...
2017: Theranostics
https://www.readbyqxmd.com/read/28429734/neuroprotective-pentapeptide-cn-105-is-associated-with-reduced-sterile-inflammation-and-improved-functional-outcomes-in-a-traumatic-brain-injury-murine-model
#4
Daniel T Laskowitz, Haichen Wang, Tony Chen, David T Lubkin, Viviana Cantillana, Tian Ming Tu, Dawn Kernagis, Guanen Zhou, Gary Macy, Bradley J Kolls, Hana N Dawson
At present, there are no proven pharmacological treatments demonstrated to improve long term functional outcomes following traumatic brain injury(TBI). In the setting of non-penetrating TBI, sterile brain inflammatory responses are associated with the development of cerebral edema, intracranial hypertension, and secondary neuronal injury. There is increasing evidence that endogenous apolipoprotein E(apoE) modifies the neuroinflammatory response through its role in downregulating glial activation, however, the intact apoE holoprotein does not cross the blood-brain barrier due to its size...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28406232/peptidoglycan-o-acetylation-increases-in-response-to-vancomycin-treatment-in-vancomycin-resistant-enterococcus-faecalis
#5
James D Chang, Erin E Foster, Ashley G Wallace, Sung Joon Kim
Vancomycin resistance is conferred upon vancomycin-resistant enterococci (VRE) through the replacement of peptidoglycan (PG) stem terminal d-Ala-d-Ala with d-Ala-d-Lac. The d-Ala-d-Lac incorporation can affect both the fitness and virulence of VRE. Here we comprehensively investigate the changes to PG composition in vancomycin-resistant Enterococcus faecalis following the growth in presence of vancomycin using liquid chromatography-mass spectrometry. Using high-resolution mass spectrometry, 104 unique muropeptides fragments were identified and the relative abundance of each fragment was accurately quantified by integrating the ion current of a selected ion using extracted-ion chromatogram...
April 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28398740/structural-reassignment-and-absolute-stereochemistry-of-madurastatin-c1-mbj-0034-and-the-related-aziridine-siderophores-madurastatins-a1-b1-and-mbj-0035
#6
Andrew R Tyler, Hamed Mosaei, Stephanie Morton, Paul G Waddell, Corinne Wills, William McFarlane, Joe Gray, Michael Goodfellow, Jeff Errington, Nick Allenby, Nikolay Zenkin, Michael J Hall
The madurastatins are pentapeptide siderophores originally described as containing an unusual salicylate-capped N-terminal aziridine ring. Isolation of madurastatin C1 (1) (also designated MBJ-0034), from Actinomadura sp. DEM31376 (itself isolated from a deep sea sediment), prompted structural reevaluation of the madurastatin siderophores, in line with the recent work of Thorson and Shaaban. NMR spectroscopy in combination with partial synthesis allowed confirmation of the structure of madurastatin C1 (1) as containing an N-terminal 2-(2-hydroxyphenyl)oxazoline in place of the originally postulated aziridine, while absolute stereochemistry was determined via Harada's advanced Marfey's method...
April 11, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28382306/apolipoprotein-e-mimetic-peptide-cn-105-improves-outcomes-in-ischemic-stroke
#7
Tian Ming Tu, Brad J Kolls, Erik J Soderblom, Viviana Cantillana, Paul Durham Ferrell, M Arthur Moseley, Haichen Wang, Hana N Dawson, Daniel T Laskowitz
OBJECTIVE: At present, the absence of a pharmacological neuroprotectant represents an important unmet clinical need in the treatment of ischemic and traumatic brain injury. Recent evidence suggests that administration of apolipoprotein E mimetic therapies represent a viable therapeutic strategy in this setting. We investigate the neuroprotective and anti-inflammatory properties of the apolipoprotein E mimetic pentapeptide, CN-105, in a microglial cell line and murine model of ischemic stroke...
April 2017: Annals of Clinical and Translational Neurology
https://www.readbyqxmd.com/read/28363829/integrin-signaling-potentiates-transforming-growth-factor-beta-1-tgf-%C3%AE-1-dependent-down-regulation-of-e-cadherin-expression-important-implications-for-epithelial-to-mesenchymal-transition-emt-in-renal-cell-carcinoma
#8
B Feldkoren, R Hutchinson, Y Rapaport, A Mahajan, V Margulis
Signal transduction through the transforming growth factor-beta 1 (TGF-β1) pathway affects epithelial to mesenchymal transition (EMT), partly by modulation of E-Cadherin expression. The concurrent impact of extracellular matrix driven regulation of integrin signaling on EMT has not been well characterized. We assessed the cumulative effect and molecular mechanisms of TGF-β1 and integrin signal transduction on E-Cadherin in a renal cell cancer (RCC) model. Stimulation of RCC cells with TGF-β1 demonstrated a three-fold increased expression of integrin αv...
March 28, 2017: Experimental Cell Research
https://www.readbyqxmd.com/read/28343865/regulatory-role-of-rna-chaperone-tdp-43-for-rna-misfolding-and-repeat-associated-translation-in-sca31
#9
Taro Ishiguro, Nozomu Sato, Morio Ueyama, Nobuhiro Fujikake, Chantal Sellier, Akemi Kanegami, Eiichi Tokuda, Bita Zamiri, Terence Gall-Duncan, Mila Mirceta, Yoshiaki Furukawa, Takanori Yokota, Keiji Wada, J Paul Taylor, Christopher E Pearson, Nicolas Charlet-Berguerand, Hidehiro Mizusawa, Yoshitaka Nagai, Kinya Ishikawa
Microsatellite expansion disorders are pathologically characterized by RNA foci formation and repeat-associated non-AUG (RAN) translation. However, their underlying pathomechanisms and regulation of RAN translation remain unknown. We report that expression of expanded UGGAA (UGGAAexp) repeats, responsible for spinocerebellar ataxia type 31 (SCA31) in Drosophila, causes neurodegeneration accompanied by accumulation of UGGAAexp RNA foci and translation of repeat-associated pentapeptide repeat (PPR) proteins, consistent with observations in SCA31 patient brains...
April 5, 2017: Neuron
https://www.readbyqxmd.com/read/28320719/antibiotic-effects-on-methicillin-resistant-staphylococcus-aureus-cytoplasmic-peptidoglycan-intermediate-levels-evidence-for-potential-metabolite-level-regulatory-loops
#10
Harika Vemula, Navid J Ayon, Alloch Burton, William G Gutheil
Cytoplasmic peptidoglycan (PG) precursor levels were determined in methicillin resistant S. aureus (MRSA) after exposure to several cell wall targeting antibiotics. Three experiments were performed: 1) Exposure to 4x MIC levels (acute). 2) Exposure to sub-MIC levels (sub-acute). 3) A time course of the effect of vancomycin. In acute exposure experiments, fosfomycin increased UDP-GlcNAc, as expected, and resulted in substantially lower levels of total UDP-linked metabolite accumulation relative to other pathway inhibitors, indicating reduced entry into this pathway...
March 20, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28318942/cyclic-mu-opioid-receptor-ligands-containing-multiple-n-methylated-amino-acid-residues
#11
Anna Adamska-Bartłomiejczyk, Anna Janecka, Márton Richárd Szabó, Maria Camilla Cerlesi, Girolamo Calo, Alicja Kluczyk, Csaba Tömböly, Attila Borics
In this study we report the in vitro activities of four cyclic opioid peptides with various sequence length/macrocycle size and N-methylamino acid residue content. N-Methylated amino acids were incorporated and cyclization was employed to enhance conformational rigidity to various extent. The effect of such modifications on ligand structure and binding properties were studied. The pentapeptide containing one endocyclic and one exocyclic N-methylated amino acid displayed the highest affinity to the mu-opioid receptor...
March 7, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28303616/bike-peptides-a-ride-through-the-membrane
#12
Júlia García-Pindado, Soledad Royo, Meritxell Teixidó, Ernest Giralt
Several natural peptides have a biaryl or biaryl ether motif in their biologically active structures. A model bicyclic pentapeptide containing a biaryl bridge has been synthesized by solid-phase peptide synthesis combining on-resin Suzuki and Miyaura cross-coupling reactions. Its biological properties in terms of permeability, stability and cytotoxicity have been studied, demonstrating the positive contribution of the biaryl bridge, excellent membrane penetration and serum stability Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd...
March 16, 2017: Journal of Peptide Science: An Official Publication of the European Peptide Society
https://www.readbyqxmd.com/read/28287429/d-amino-acid-position-influences-the-anticancer-activity-of-galaxamide-analogs-an-apoptotic-mechanism-study
#13
Defa Bai, Siming Yu, Shenghui Zhong, Bingxin Zhao, Shaoling Qiu, Jianwei Chen, Jignesh Lunagariya, Xiaojian Liao, Shihai Xu
Galaxamide, an extract from Galaxaura filamentosa, is a cyclic pentapeptide containing five l-leucines. Due to the particular cyclic structure and the excellent anticancer activity, synthesis of Galaxamide and its analogs and their subsequent bio-applications have attracted great attention. In the present work, we synthesized six Galaxamide analogs by replacing one of the l-leucines with phenylalanine and varying the d-amino acid position. The anticancer effect of the synthesized Galaxamide analogs was tested against four in vitro human cancer cell lines, human hepatocellular cells (HepG₂), human breast cancer cell (MCF-7), human breast adenocarcinoma cells (MDA-MB-435) and a human cervical carcinoma cell line (Hela)...
March 10, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28280373/effect-of-a-small-molecule-lipid-ii-binder-on-bacterial-cell-wall-stress
#14
Jakob Malin, Amol C Shetty, Sean C Daugherty, Erik Ph de Leeuw
We have recently identified small molecule compounds that act as binders of Lipid II, an essential precursor of bacterial cell wall biosynthesis. Lipid II comprised a hydrophilic head group that includes a peptidoglycan subunit composed of N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc) coupled to a short pentapeptide moiety. This headgroup is coupled to a long bactoprenol chain via a pyrophosphate group. Here, we report on the cell wall activity relationship of dimethyl-3-methyl(phenyl)amino-ethenylcyclohexylidene-propenyl-3-ethyl-1,3-benzothiazolium iodide (compound 5107930) obtained by functional and genetic analyses...
2017: Infection and Drug Resistance
https://www.readbyqxmd.com/read/28275110/acute-effects-of-n-terminal-progastrin-fragments-on-gastric-acid-secretion-in-man
#15
Jens P Goetze, Carsten P Hansen, Jens F Rehfeld
We previously identified an N-terminal fragment of progastrin in human antrum and plasma, where it circulates in high concentrations. In this study, we examined the effects of N-terminal progastrin fragments on gastric acid secretion by infusion in healthy individuals. Increasing doses of progastrin fragment 1-35 were infused intravenously during constant gastric acid stimulation by gastrin-17. In addition, the effects of progastrin fragment 1-35, fragment 6-35, and fragment 1-19 on gastrin-17 stimulated acid secretion were tested...
March 2017: Physiological Reports
https://www.readbyqxmd.com/read/28248311/sansanmycin-natural-product-analogues-as-potent-and-selective-anti-mycobacterials-that-inhibit-lipid-i-biosynthesis
#16
Anh T Tran, Emma E Watson, Venugopal Pujari, Trent Conroy, Luke J Dowman, Andrew M Giltrap, Angel Pang, Weng Ruh Wong, Roger G Linington, Sebabrata Mahapatra, Jessica Saunders, Susan A Charman, Nicholas P West, Timothy D H Bugg, Julie Tod, Christopher G Dowson, David I Roper, Dean C Crick, Warwick J Britton, Richard J Payne
Tuberculosis (TB) is responsible for enormous global morbidity and mortality, and current treatment regimens rely on the use of drugs that have been in use for more than 40 years. Owing to widespread resistance to these therapies, new drugs are desperately needed to control the TB disease burden. Herein, we describe the rapid synthesis of analogues of the sansanmycin uridylpeptide natural products that represent promising new TB drug leads. The compounds exhibit potent and selective inhibition of Mycobacterium tuberculosis, the etiological agent of TB, both in vitro and intracellularly...
March 1, 2017: Nature Communications
https://www.readbyqxmd.com/read/28241893/parasitism-as-the-main-factor-shaping-peptide-vocabularies-in-current-organisms
#17
Michaela Zemková, Daniel Zahradník, Martin Mokrejš, Jaroslav Flegr
Self/non-self-discrimination by vertebrate immune systems is based on the recognition of the presence of peptides in proteins of a parasite that are not contained in the proteins of a host. Therefore, a reduction of the number of 'words' in its own peptide vocabulary could be an efficient evolutionary strategy of parasites for escaping recognition. Here, we compared peptide vocabularies of 30 endoparasitic and 17 free-living unicellular organisms and also eight multicellular parasitic and 16 multicellular free-living organisms...
February 28, 2017: Parasitology
https://www.readbyqxmd.com/read/28230109/pentose-sugars-inhibit-metabolism-and-increase-expression-of-an-agrd-type-cyclic-pentapeptide-in-clostridium-thermocellum
#18
Tobin J Verbeke, Richard J Giannone, Dawn M Klingeman, Nancy L Engle, Thomas Rydzak, Adam M Guss, Timothy J Tschaplinski, Steven D Brown, Robert L Hettich, James G Elkins
Clostridium thermocellum could potentially be used as a microbial biocatalyst to produce renewable fuels directly from lignocellulosic biomass due to its ability to rapidly solubilize plant cell walls. While the organism readily ferments sugars derived from cellulose, pentose sugars from xylan are not metabolized. Here, we show that non-fermentable pentoses inhibit growth and end-product formation during fermentation of cellulose-derived sugars. Metabolomic experiments confirmed that xylose is transported intracellularly and reduced to the dead-end metabolite xylitol...
February 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28134244/bacillus-subtilis-biofilm-extends-caenorhabditis-elegans-longevity-through-downregulation-of-the-insulin-like-signalling-pathway
#19
Verónica Donato, Facundo Rodríguez Ayala, Sebastián Cogliati, Carlos Bauman, Juan Gabriel Costa, Cecilia Leñini, Roberto Grau
Beneficial bacteria have been shown to affect host longevity, but the molecular mechanisms mediating such effects remain largely unclear. Here we show that formation of Bacillus subtilis biofilms increases Caenorhabditis elegans lifespan. Biofilm-proficient B. subtilis colonizes the C. elegans gut and extends worm lifespan more than biofilm-deficient isogenic strains. Two molecules produced by B. subtilis - the quorum-sensing pentapeptide CSF and nitric oxide (NO) - are sufficient to extend C. elegans longevity...
January 30, 2017: Nature Communications
https://www.readbyqxmd.com/read/28118510/pentapeptide-rich-peptidoglycan-at-the-bacillus-subtilis-cell-division-site
#20
Danae Morales Angeles, Yun Liu, Alwin M Hartman, Marina Borisova, Anabela de Sousa Borges, Niels de Kok, Katrin Beilharz, Jan-Willem Veening, Christoph Mayer, Anna K H Hirsch, Dirk-Jan Scheffers
Peptidoglycan (PG), the major component of the bacterial cell wall, is one large macromolecule. To allow for the different curvatures of PG at cell poles and division sites, there must be local differences in PG architecture and eventually also chemistry. Here we report such local differences in the Gram-positive rod-shaped model organism Bacillus subtilis. Single-cell analysis after antibiotic treatment and labeling of the cell wall with a fluorescent analogue of vancomycin or the fluorescent D-amino acid analogue (FDAA) HCC-amino-D-alanine revealed that PG at the septum contains muropeptides with unprocessed stem peptides (pentapeptides)...
January 24, 2017: Molecular Microbiology
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