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https://www.readbyqxmd.com/read/28223213/interaction-between-chitosan-and-its-related-enzymes-a-review
#1
REVIEW
Shoko Shinya, Tamo Fukamizo
Chitosan-related enzymes including chitosanases, exo-β-glucosaminidases, and enzymes having chitosan-binding modules recognize ligands through electrostatic interactions between the acidic amino acids in proteins and amino groups of chitosan polysaccharides. However, in GH8 chitosanases, several aromatic residues are also involved in substrate recognition through stacking interactions, and these enzymes consequently hydrolyze β-1,4-glucan as well as chitosan. The binding grooves of these chitosanases are extended and opened at both ends of the grooves, so that the enzymes can clamp a long chitosan polysaccharide...
February 18, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28223024/construction-of-a-library-of-structurally-diverse-ribonucleopeptides-with-catalytic-groups
#2
Tomoki Tamura, Shun Nakano, Eiji Nakata, Takashi Morii
Functional screening of structurally diverse libraries consisting of proteins or nucleic acids is an effective method to obtain receptors or aptamers with unique molecular recognition characteristics. However, further modification of these selected receptors to exert a newly desired function is still a challenging task. We have constructed a library of structurally diverse ribonucleopeptides (RNPs) that are modified with a catalytic group, in which the catalytic group aligns with various orientations against the ATP binding pocket of RNA subunit...
February 10, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28222397/a-novel-approach-towards-design-synthesis-and-evaluation-of-some-schiff-base-analogues-of-2-aminopyridine-and-2-aminobezothiazole-against-hepatocellular-carcinoma
#3
Shinu Chacko, Subir Samanta
Hepatocellular carcinoma is the most common primary malignancy of the liver with poor prognosis. In this study novel, Schiff's bases of 2-aminopyridine (SSSC-26 to 31) and 2-aminobenzothiazole (SSSC-32 to 37) were designed, synthesised and evaluated for antioxidant potential using DPPH method, and anti-hepatocellular carcinoma property using diethylnitrosamine (DEN) induced hepatocellular carcinoma rat model. The in-silico pharmacokinetic, rule of five and toxicity studies reveals that all the leads have an excellent intrinsic quality and sufficient structural features necessary for an oral activity...
February 18, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28221244/hla-amino-acid-polymorphisms-and-kidney-allograft-survival
#4
Malek Kamoun, Keith P McCullough, Martin Maiers, Marcelo A Fernandez Vina, Hongzhe Li, Valerie Teal, Alan B Leichtman, Robert M Merion
BACKGROUND: The association of HLA mismatching with kidney allograft survival has been well established. We examined whether amino acid mismatches at the antigen recognition site of HLA molecules represent independent and incremental risk factors for kidney graft failure (GF) beyond those mismatches assessed at the antigenic (2-digit) specificity. METHODS: Data on 240,024 kidney transplants performed between 1987 and 2009 were obtained from the Scientific Registry of Transplant Recipients...
February 18, 2017: Transplantation
https://www.readbyqxmd.com/read/28220887/mass-spectrometric-analysis-of-trpm6-and-trpm7-phosphorylation-reveals-regulatory-mechanisms-of-the-channel-kinases
#5
Na Cai, Zhiyong Bai, Vikas Nanda, Loren W Runnels
TRPM7 and TRPM6 were the first identified bifunctional channels to contain their own kinase domains, but how these channel-kinases are regulated is poorly understood. Previous studies identified numerous phosphorylation sites on TRPM7, but very little is known about TRPM6 phosphorylation or sites on TRPM7 transphosphorylated by TRPM6. Our mass spectrometric analysis of homomeric and heteromeric TRPM7 and TRPM6 channels identified phosphorylation sites on both proteins, as well as several prominent sites on TRPM7 that are commonly modified through autophosphorylation and transphosphorylation by TRPM6...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28220706/human-cannabinoid-receptor-2-ligand-interaction-motif-transmembrane-helix-2-cysteine-c2-59-89-as-determinant-of-classical-cannabinoid-agonist-activity-and-binding-pose
#6
Han Zhou, Yan Peng, Aneetha Halikhedkar, Pusheng Fan, David R Janero, Ganesh A Thakur, Richard Warren Mercier, Xin Sun, Xiaoyu Ma, Alexandros Makriyannis
Cannabinoid receptor 2 (CB2R)-dependent signaling is implicated in neuronal physiology and immune surveillance by brain microglia. Selective CB2R agonists hold therapeutic promise for inflammatory and other neurological disorders. Information on human CB2R (hCB2R) ligand-binding and functional domains is needed to inform the rational design and optimization of candidate drug-like hCB2R agonists. Prior demonstration that hCB2R transmembrane helix 2 (TMH2) cysteine C2.59(89) reacts with small-molecule methanethiosulfonates showed that this cysteine residue is accessible to sulfhydryl derivatization reagents...
February 21, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28213174/evidence-of-the-presence-of-a-calmodulin-sensitive-plasma-membrane-ca-2-atpase-in-trypanosoma-equiperdum
#7
María Carolina Pérez-Gordones, José Rubén Ramírez-Iglesias, Vincenza Cervino, Graciela L Uzcanga, Gustavo Benaim, Marta Mendoza
Trypanosoma equiperdum belongs to the subgenus Trypanozoon, which has a significant socio-economic impact by limiting animal protein productivity worldwide. Proteins involved in the intracellular Ca(2+) regulation are prospective chemotherapeutic targets since several drugs used in experimental treatment against trypanosomatids exert their action through the disruption of the parasite intracellular Ca(2+) homeostasis. Therefore, the plasma membrane Ca(2+)-ATPase (PMCA) is considered as a potential drug target...
February 14, 2017: Molecular and Biochemical Parasitology
https://www.readbyqxmd.com/read/28207833/structure-kinetic-characterization-and-subcellular-localization-of-the-two-ribulose-5-phosphate-epimerase-isoenzymes-from-trypanosoma-cruzi
#8
Soledad Natalia Gonzalez, Wanda Mariela Valsecchi, Dante Maugeri, José María Delfino, Juan José Cazzulo
The enzyme of the pentose phosphate pathway (PPP) ribulose-5-phosphate-epimerase (RPE) is encoded by two genes present in the genome of Trypanosoma cruzi CL Brener clone: TcRPE1 and TcRPE2. Despite high sequence similarity at the amino acid residue level, the recombinant isoenzymes show a strikingly different kinetics. Whereas TcRPE2 follows a typical michaelian behavior, TcRPE1 shows a complex kinetic pattern, displaying a biphasic curve, suggesting the coexistence of -at least- two kinetically different molecular forms...
2017: PloS One
https://www.readbyqxmd.com/read/28202754/jak-stat-signaling-pathways-and-inhibitors-affect-reversion-of-envelope-mutated-hiv-1
#9
Yudong Quan, Hongtao Xu, Yingshan Han, Thibault Mesplède, Mark A Wainberg
HIV can spread by both cell-free and cell-to-cell transmission. Here, we show that numerous of the amino acid changes in Env that are close to the CD4 binding pocket can affect HIV replication. We generated a number of mutant viruses that were unable to infect T cells as cell-free viruses but were nevertheless able to infect certain T cell lines as cell-associated viruses, followed by reversion to wild type. However, the activation of JAK-STAT signaling pathways caused inhibition of such cell-to-cell infection as well as the reversion of multiple HIV Env mutants that displayed differences in ability to bind to the CD4 receptor...
February 15, 2017: Journal of Virology
https://www.readbyqxmd.com/read/28194270/total-synthesis-of-a-key-series-of-vinblastines-modified-at-c4-that-define-the-importance-and-surprising-trends-in-activity
#10
Shouliang Yang, Kuppusamy Sankar, Colin K Skepper, Timothy J Barker, John C Lukesh, Daniel M Brody, Manuela M Brütsch, Dale L Boger
The total synthesis and evaluation of a key systematic series of vinblastines that incorporate the first deep-seated changes to the substituent at C4 are detailed. The synthetic approach features an expanded and redefined scope of a 1,3,4-oxadiazole [4 + 2]/[3 + 2] cycloaddition cascade in which electronically mismatched electron-deficient trisubstituted alkenes and unactivated trisubstituted alkenes were found to productively initiate the cycloaddition cascade with tethered electron-deficient 1,3,4-oxadiazoles...
February 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28193765/a-novel-chemical-inhibitor-of-aba-signaling-targets-all-aba-receptors
#11
Ya-Jin Ye, Lijuan Zhou, Xue Liu, Hao Liu, Deqiang Li, Minjie Cao, Haifeng Chen, Lin Xu, Jiankang Zhu, Yang Zhao
Abscisic acid (ABA), the most important stress-induced phytohormone, regulates seed dormancy, germination, plant senescence and abiotic stress response. ABA signaling is repressed by protein phosphatases 2C (PP2Cs), then ABA binds to its receptor of the PYR/PYL/RCAR family, which in turn inhibits PP2Cs and activates downstream ABA signaling. The agonist/antagonist of ABA receptors have the potential to unveil the ABA signaling machinery and to become lead compounds for agrochemicals, however, up to now, no broad-spectrum antagonists of ABA receptors blocking all PYR/PYL-PP2C interactions have been identified...
February 13, 2017: Plant Physiology
https://www.readbyqxmd.com/read/28192928/revealing-the-effect-of-protein-weak-adsorption-to-nanoparticles-on-the-interaction-between-the-desorbed-protein-and-its-binding-partner-by-surface-enhanced-infrared-spectroelectrochemistry
#12
Li Liu, Li Zeng, Lie Wu, Xiue Jiang
In recent years, the properties of protein corona have attracted intense interest in the field of nanobio interface, but a long-ignored research issue is how the desorbed proteins suffering from conformational change upon weak association with nanoparticles affect their functional properties when further interacting with their downstream protein partners. In this Article, surface-enhanced infrared absorption spectroscopy (SEIRAS) and electrochemical cyclic voltammetry were used to study the adsorption and redox properties of the soluble cytochrome c (cyt c) on 11-mercaptoundecanoic acid (MUA) self-assembled monolayer (SAM) after weakly binding to and then desorbed from nano-TiO2...
February 13, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28191842/synthesis-and-functional-characterization-of-novel-sialyl-lewisx-mimic-decorated-liposomes-for-e-selectin-mediated-targeting-to-inflamed-endothelial-cells
#13
Chanikarn Chantarasrivong, Akiharu Ueki, Ryutaro Ohyama, Johan Unga, Shinya Nakamura, Isao Nakanishi, Yuriko Higuchi, Shigeru Kawakami, Hiromune Ando, Akihiro Imamura, Hideharu Ishida, Fumiyoshi Yamashita, Makoto Kiso, Mitsuru Hashida
Sialyl LewisX (sLeX) is a natural ligand of E-selectin that is overexpressed by inflamed and tumor endothelium. Although sLeX is a potential ligand for drug targeting, synthesis of the tetrasaccharide is complicated with many reaction steps. In this study, structurally simplified novel sLeX analogs were designed and linked with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethyleneglycol-2000 (DSPE-PEG) for E-selectin-mediated liposomal delivery. The sLeX structural simplification strategies include (1) replacement of the Gal-GlcNAc disaccharide unit with lactose to reduce many initial steps and (2) substitution of neuraminic acid with a negatively charged group, i...
February 13, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28186999/design-sythesis-and-evaluation-of-a-series-of-3-or-4-alkoxy-substituted-phenoxy-derivatives-as-ppars-agonists
#14
Jun Zhang, Xue-Jiao Wang, Xin Liu, Yi Huan, Miao-Miao Yang, Zhu-Fang Shen, Wen-Qing Jia, Zhi Jing, Shu-Qing Wang, Wei-Ren Xu, Xian-Chao Cheng, Run-Ling Wang
Peroxisome proliferators-activated receptors (PPARα, γ and δ) are potentially effective targets for Type 2 diabetes mellitus therapy. The severe effects of known glitazones and the successfully approved agents (saroglitazar and lobeglitazone) motivated us to study novelly potent PPARs drugs with improved safety profile. In this work, we received 15 carboxylic acids based on the combination principle to integrate the polar head of bezafibrate with the hydrophobic tail of pioglitazone. Another 12 tetrazoles based on the bioisosterism principle were obtained accordingly...
February 8, 2017: Oncotarget
https://www.readbyqxmd.com/read/28182094/hemoglobins-likely-function-as-peroxidase-in-blood-clam-tegillarca-granosa-hemocytes
#15
Sufang Wang, Xiaopei Yu, Zhihua Lin, Shunqin Zhang, Liangyi Xue, Qinggang Xue, Yongbo Bao
Hemoglobins are a group of respiratory proteins principally functioning in transport of oxygen and carbon dioxide in red blood cells of all vertebrates and some invertebrates. The blood clam T. granosa is one of the few invertebrates that have hemoglobin-containing red hemocytes. In the present research, the peroxidase activity of T. granosa hemoglobins (Tg-Hbs) was characterized and the associated mechanism of action was deciphered via structural comparison with other known peroxidases. We detected that purified Tg-Hbs catalyzed the oxidation of phenolic compounds in the presence of exogenous H2O2...
2017: Journal of Immunology Research
https://www.readbyqxmd.com/read/28182054/design-formulation-and-physicochemical-evaluation-of-periodontal-propolis-mucoadhesive-gel
#16
Abolfazl Aslani, Negar Malekpour
BACKGROUND: Periodontitis is a disease of tooth supporting tissues, and Gram-negative Bacteria are the main cause of this. Propolis has antibacterial, anti-inflammatory, and antioxidant effects due to its high polyphenol and flavonoids content. The aim of this study is the formulation of a mucoadhesive gel containing concentrated extract of propolis for treatment of periodontitis. MATERIALS AND METHODS: Formulations containing carbopol 940, sodium carboxymethylcellulose (NaCMC), hydroxypropyl methylcellulose K4M, and propolis extract were prepared...
November 2016: Dental Research Journal
https://www.readbyqxmd.com/read/28180917/improvement-of-enzyme-activity-of-%C3%AE-1-3-1-4-glucanase-from-paenibacillus-sp-x4-by-error-prone-pcr-and-structural-insights-of-mutated-residues
#17
Seung Cheol Baek, Thien-Hoang Ho, Hyun Woo Lee, Won Kyeong Jung, Hyo-Seung Gang, Lin-Woo Kang, Hoon Kim
β-1,3-1,4-Glucanase (BGlc8H) from Paenibacillus sp. X4 was mutated by error-prone PCR or truncated using termination primers to improve its enzyme properties. The crystal structure of BGlc8H was determined at a resolution of 1.8 Å to study the possible roles of mutated residues and truncated regions of the enzyme. In mutation experiments, three clones of EP 2-6, 2-10, and 5-28 were finally selected that exhibited higher specific activities than the wild type when measured using their crude extracts. Enzyme variants of BG2-6, BG2-10, and BG5-28 were mutated at two, two, and six amino acid residues, respectively...
February 8, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28179428/breaking-confinement-unconventional-peptide-presentation-by-major-histocompatibility-mhc-class-i-allele-hla-a-02-01
#18
Soumya G Remesh, Massimo Andreatta, Ge Ying, Thomas Kaever, Morten Nielsen, Curtis McMurtrey, William Hildebrand, Bjoern Peters, Dirk M Zajonc
Peptide antigen-presentation by Major Histocompatibility Class (MHC) I proteins initiates CD8+ T cell mediated immunity against pathogens and cancers. MHC I molecules typically bind peptides with nine amino acids in length with both ends tucked inside the major A and F binding pocket. It has been known for a while that longer peptides can also bind by either bulging out of the groove in the middle of the peptide or by binding in a zig-zag fashion inside the groove. In a recent study, we identified an alternative binding conformation of naturally occurring peptides from Toxoplasma gondii bound by HLA-A*02:01...
February 8, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28178586/the-relationship-between-insulin-resistance-and-periodontitis-is-not-affected-by-mediterranean-diet-in-a-spanish-population
#19
M Pulido-Moran, P Bullon, J M Morillo, M Battino, J L Quiles, MCarmen Ramirez-Tortosa
OBJETIVE: To examine the insulin resistance measured by surrogate indices in subjects with and without periodontitis and to find out any correlation among dietary intake with insulin resistance. DESIGN: Fifty-five patients were recruited to participate in this cross-sectional study. Insulin resistance measured by the homoeostasis model assessment (HOMA-IR) and the quantitative insulin sensitivity check index moreover glycaemia, creatinine, uric acid, high density lipoproteins, low density lipoproteins, very low density lipoproteins and triglycerides among others...
February 1, 2017: Archives of Oral Biology
https://www.readbyqxmd.com/read/28173762/binding-affinity-of-five-pbps-to-ostrinia-sex-pheromones
#20
Tiantao Zhang, Yaqi Sun, Kevin W Wanner, Brad S Coates, Kanglai He, Zhenying Wang
BACKGROUND: Pheromone binding proteins (PBPs) of male Lepidoptera function in chemical communication, mate attraction and recognition. Directional selection was previously predicted between PBP3 orthologs of Ostrinia furnacalis and Ostrinia nubilalis were interpreted as being involved in sexual isolation. RESULTS: In vitro assays show that recombinant male OfurPBP3 bound O. furnacalis sex pheromones, Z-12-tetradecenyl acetate (Z12-14:OAc) and E-12-tetradecenyl acetate (E12-14:OAc), as well as to ECB pheromones Z11- and E11-14:OAc...
February 7, 2017: BMC Molecular Biology
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