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5-ala nmr

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https://www.readbyqxmd.com/read/28858505/synthesis-of-intrinsically-blue-colored-bis-nitronyl-nitroxide-peptidomimetic-templates-and-their-conformational-preferences-as-revealed-by-a-combined-spectroscopic-analysis
#1
Marta De Zotti, Karen Wright, Edouard d'Aboville, Antonio Toffoletti, Claudio Toniolo, Giovanna Longhi, Giuseppe Mazzeo, Sergio Abbate, Fernando Formaggio
The intrinsically blue-colored Ullman imidazolinyl nitronyl nitroxide (NN) mono-radicals have found various applications, in particular as spin probes and organic magnetic materials. Here, we present the solution-phase synthesis, extensive characterization, and conformational analysis of the first peptidomimetics with two pendant, chiral nitronyl nitroxide free radical units. Two (R)-Aic(NN) residues, where Aic(NN) is 2-amino-5-nitronylnitroxide-indan-2-carboxylic acid, have been inserted at positions i and i+3 of the pentapeptide Boc-(R)-Aic(NN)-(Ala)2-(R)-Aic(NN)-Ala-OMe and the hexapeptide Boc-[Ala-(R)-Aic(NN)-Ala]2-OMe as well...
September 18, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28856561/site-selective-13-c-labeling-of-histidine-and-tryptophan-using-ribose
#2
Ulrich Weininger
Experimental studies on protein dynamics at atomic resolution by NMR-spectroscopy in solution require isolated (1)H-X spin pairs. This is the default scenario in standard (1)H-(15)N backbone experiments. Side chain dynamic experiments, which allow to study specific local processes like proton-transfer, or tautomerization, require isolated (1)H-(13)C sites which must be produced by site-selective (13)C labeling. In the most general way this is achieved by using site-selectively (13)C-enriched glucose as the carbon source in bacterial expression systems...
August 30, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/28846849/cyclic-hexapeptide-dimers-antatollamides-a-and-b-from-the-ascidian-didemnum-molle-a-tryptophan-derived-auxiliary-for-l-and-d-amino-acid-assignments
#3
Mariam N Salib, Tadeusz F Molinski
Two dimerized cyclic hexapeptides, antatollamides A (1) and B (2), were isolated from the colonial ascidian Didemnum molle collected in Pohnpei. The amino acid compositions and sequences were determined by interpretation of MS and 1D and 2D NMR data. Raney Ni reduction of antatollamide A cleaved the dimer to the corresponding monomeric cyclic hexapeptide with replacement of Cys by Ala. The amino acid configuration of 1 was established, after total hydrolysis, by derivatization with a new chiral reagent, (5-fluoro-2,4-dinitrophenyl)-N(α)-l-tryptophanamide (FDTA), prepared from l-Trp, followed by LCMS analysis; all amino acids were found to be l-configured except for d-Ala...
September 18, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28766333/monitoring-hydrogen-exchange-during-protein-folding-by-fast-pressure-jump-nmr-spectroscopy
#4
T Reid Alderson, Cyril Charlier, Dennis A Torchia, Philip Anfinrud, Ad Bax
A method is introduced that permits direct observation of the rates at which backbone amide hydrogens become protected from solvent exchange after rapidly dropping the hydrostatic pressure inside the NMR sample cell from denaturing (2.5 kbar) to native (1 bar) conditions. The method is demonstrated for a pressure-sensitized ubiquitin variant that contains two Val to Ala mutations. Increased protection against hydrogen exchange with solvent is monitored as a function of time during the folding process. Results for 53 backbone amides show narrow clustering with protection occurring with a time constant of ca...
August 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28437077/peptide-and-protein-dynamics-and-low-temperature-dnp-magic-angle-spinning-nmr
#5
Qing Zhe Ni, Evgeny Markhasin, Thach V Can, Björn Corzilius, Kong Ooi Tan, Alexander B Barnes, Eugenio Daviso, Yongchao Su, Judith Herzfeld, Robert G Griffin
In DNP MAS NMR experiments at ∼80-110 K, the structurally important -(13)CH3 and -(15)NH3(+) signals in MAS spectra of biological samples disappear due to the interference of the molecular motions with the (1)H decoupling. Here we investigate the effect of these dynamic processes on the NMR line shapes and signal intensities in several typical systems: (1) microcrystalline APG, (2) membrane protein bR, (3) amyloid fibrils PI3-SH3, (4) monomeric alanine-CD3, and (5) the protonated and deuterated dipeptide N-Ac-VL over 78-300 K...
May 10, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/27618034/glycerin-induced-conformational-changes-in-bombyx-mori-silk-fibroin-film-monitored-by-13-c-cp-mas-nmr-and-%C3%A2-h-dqmas-nmr
#6
Tetsuo Asakura, Masanori Endo, Misaki Hirayama, Hiroki Arai, Akihiro Aoki, Yugo Tasei
In order to improve the stiff and brittle characteristics of pure Bombyx mori (B. mori) silk fibroin (SF) film in the dry state, glycerin (Glyc) has been used as a plasticizer. However, there have been very limited studies on the structural characterization of the Glyc-blended SF film. In this study, (13)C Cross Polarization/Magic Angle Spinning nuclear magnetic resonance (CP/MAS NMR) was used to monitor the conformational changes in the films by changing the Glyc concentration. The presence of only 5 wt % Glyc in the film induced a significant conformational change in SF where Silk I* (repeated type II β-turn and no α-helix) newly appeared...
September 9, 2016: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/27605587/characterization-of-the-metabolic-profile-associated-with-serum-25-hydroxyvitamin-d-a-cross-sectional-analysis-in-population-based-data
#7
Susanne Vogt, Simone Wahl, Johannes Kettunen, Susanne Breitner, Gabi Kastenmüller, Christian Gieger, Karsten Suhre, Melanie Waldenberger, Jürgen Kratzsch, Markus Perola, Veikko Salomaa, Stefan Blankenberg, Tanja Zeller, Pasi Soininen, Antti J Kangas, Annette Peters, Harald Grallert, Mika Ala-Korpela, Barbara Thorand
BACKGROUND: Numerous observational studies have observed associations between vitamin D deficiency and cardiometabolic diseases, but these findings might be confounded by obesity. A characterization of the metabolic profile associated with serum 25-hydroxyvitamin D [25(OH)D] levels, in general and stratified by abdominal obesity, may help to untangle the relationship between vitamin D, obesity and cardiometabolic health. METHODS: Serum metabolomics measurements were obtained from a nuclear magnetic resonance spectroscopy (NMR)- and a mass spectrometry (MS)-based platform...
September 7, 2016: International Journal of Epidemiology
https://www.readbyqxmd.com/read/27440045/ionization-properties-of-histidine-residues-in-the-lipid-bilayer-membrane-environment
#8
Ashley N Martfeld, Denise V Greathouse, Roger E Koeppe
We address the critically important ionization properties of histidine side chains of membrane proteins, when exposed directly to lipid acyl chains within lipid bilayer membranes. The problem is important for addressing general principles that may underlie membrane protein function. To this end, we have employed a favorable host peptide framework provided by GWALP23 (acetyl-GGALW(5)LALALALALALALW(19)LAGA-amide). We inserted His residues into position 12 or 14 of GWALP23 (replacing either Leu(12) or Leu(14)) and incorporated specific [(2)H]Ala labels within the helical core sequence...
September 2, 2016: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/27398680/probing-the-binding-of-cu-2-ions-to-a-fragment-of-the-a%C3%AE-1-42-polypeptide-using-fluorescence-spectroscopy-isothermal-titration-calorimetry-and-molecular-dynamics-simulations
#9
Joanna Makowska, Krzysztof Żamojć, Dariusz Wyrzykowski, Wioletta Żmudzińska, Dorota Uber, Małgorzata Wierzbicka, Wiesław Wiczk, Lech Chmurzyński
Steady-state and time-resolved fluorescence quenching measurements supported by isothermal titration calorimetry (ITC) and molecular dynamics simulations (MD), with the NMR-derived restraints, were used to investigate the interactions of Cu(2+) ions with a fragment of the Aβ(1-42) polypeptide, Aβ(5-16) with the following sequence: Ac-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Lys-NH2, denoted as HZ1. The studies presented in this paper, when compared with our previous results (Makowska et al., Spectrochim...
September 2016: Biophysical Chemistry
https://www.readbyqxmd.com/read/27278961/biotransformation-and-rearrangement-of-laromustine
#10
Alaa-Eldin F Nassar, Adam V Wisnewski, Ivan King
This review highlights the recent research into the biotransformations and rearrangement of the sulfonylhydrazine-alkylating agent laromustine. Incubation of [(14)C]laromustine with rat, dog, monkey, and human liver microsomes produced eight radioactive components (C-1 to C-8). There was little difference in the metabolite profile among the species examined, partly because NADPH was not required for the formation of most components, which instead involved decomposition and/or hydrolysis. The exception was C-7, a hydroxylated metabolite, largely formed by CYP2B6 and CYP3A4/5...
August 2016: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/27243469/the-carboxyl-terminus-of-eremomycin-facilitates-binding-to-the-non-d-ala-d-ala-segment-of-the-peptidoglycan-pentapeptide-stem
#11
James Chang, Hongyu Zhou, Maria Preobrazhenskaya, Peng Tao, Sung Joon Kim
Glycopeptide antibiotics inhibit cell wall biosynthesis in Gram-positive bacteria by targeting the peptidoglycan (PG) pentapeptide stem structure (l-Ala-d-iso-Gln-l-Lys-d-Ala-d-Ala). Structures of the glycopeptide complexed with a PG stem mimic have shown that the d-Ala-d-Ala segment is the primary drug binding site; however, biochemical evidence suggests that the glycopeptide-PG interaction involves more than d-Ala-d-Ala binding. Interactions of the glycopeptide with the non-d-Ala-d-Ala segment of the PG stem were investigated using solid-state nuclear magnetic resonance (NMR)...
June 21, 2016: Biochemistry
https://www.readbyqxmd.com/read/27226426/helix-nucleation-by-the-smallest-known-%C3%AE-helix-in-water
#12
Huy N Hoang, Russell W Driver, Renée L Beyer, Timothy A Hill, Aline D de Araujo, Fabien Plisson, Rosemary S Harrison, Lena Goedecke, Nicholas E Shepherd, David P Fairlie
Cyclic pentapeptides (e.g. Ac-(cyclo-1,5)-[KAXAD]-NH2 ; X=Ala, 1; Arg, 2) in water adopt one α-helical turn defined by three hydrogen bonds. NMR structure analysis reveals a slight distortion from α-helicity at the C-terminal aspartate caused by torsional restraints imposed by the K(i)-D(i+4) lactam bridge. To investigate this effect on helix nucleation, the more water-soluble 2 was appended to N-, C-, or both termini of a palindromic peptide ARAARAARA (≤5 % helicity), resulting in 67, 92, or 100 % relative α-helicity, as calculated from CD spectra...
July 11, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27008506/highly-viscous-binary-solvents-dmso-d6-glycerol-and-dmso-d6-glycerol-d8-for-polar-and-apolar-mixture-analysis-by-nmr
#13
Pedro Lameiras, Jean-Marc Nuzillard
The use of two new highly viscous binary solvents, DMSO-d6/glycerol (GL) and DMSO-d6/glycerol-d8 (GL-d8), is reported for the first time in order to give access to the individual NMR spectra of mixture components. Their high dissolution power offers a wide range of potential applications to mixture analysis, regardless of polarity. Under particular conditions of viscosity, the tumbling rate of small and medium-sized molecules slows down in solution, so that the longitudinal cross-relaxation regime favors the observation of spin diffusion...
April 19, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/26965542/metabolomic-profiling-of-statin-use-and-genetic-inhibition-of-hmg-coa-reductase
#14
MULTICENTER STUDY
Peter Würtz, Qin Wang, Pasi Soininen, Antti J Kangas, Ghazaleh Fatemifar, Tuulia Tynkkynen, Mika Tiainen, Markus Perola, Therese Tillin, Alun D Hughes, Pekka Mäntyselkä, Mika Kähönen, Terho Lehtimäki, Naveed Sattar, Aroon D Hingorani, Juan-Pablo Casas, Veikko Salomaa, Mika Kivimäki, Marjo-Riitta Järvelin, George Davey Smith, Mauno Vanhala, Debbie A Lawlor, Olli T Raitakari, Nish Chaturvedi, Johannes Kettunen, Mika Ala-Korpela
BACKGROUND: Statins are first-line therapy for cardiovascular disease prevention, but their systemic effects across lipoprotein subclasses, fatty acids, and circulating metabolites remain incompletely characterized. OBJECTIVES: This study sought to determine the molecular effects of statin therapy on multiple metabolic pathways. METHODS: Metabolic profiles based on serum nuclear magnetic resonance metabolomics were quantified at 2 time points in 4 population-based cohorts from the United Kingdom and Finland (N = 5,590; 2...
March 15, 2016: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/26887663/effect-of-metformin-therapy-on-circulating-amino-acids-in-a-randomized-trial-the-camera-study
#15
D Preiss, N Rankin, P Welsh, R R Holman, A J Kangas, P Soininen, P Würtz, M Ala-Korpela, N Sattar
AIMS: To investigate whether metformin therapy alters circulating aromatic and branched-chain amino acid concentrations, increased levels amino acid concentrations, increased levels of which have been found to predict Type 2 diabetes. METHODS: In the Carotid Atherosclerosis: Metformin for Insulin Resistance (CAMERA) study (NCT00723307), 173 individuals without Type 2 diabetes, but with coronary disease, were randomized to metformin (n=86) or placebo (n=87) for 18 months...
November 2016: Diabetic Medicine: a Journal of the British Diabetic Association
https://www.readbyqxmd.com/read/26214049/new-cyclic-tetrapeptide-from-the-coral-derived-endophytic-bacteria-brevibacterium-sp-l-4-collected-from-the-south-china-sea
#16
Bing-Xin Liu, Qiong Guo, Guang-Tian Peng, Xi-Xin He, Xiao-Jie Chen, Ling-Fang Lei, Yun Deng, Xian Jun Su, Cui-Xian Zhang
One new cyclic tetrapeptide cyclic-(Tyr-Ala-Leu-Ser) (1) along with four natural compounds firstly obtained 3H-imidazole-4-carboxylic acid (2), 2-methyl-3H-imidazole-4-carboxylic acid (3), 3-ethylidene-6-isopropyl-piperazine-2,5-dione (4), and 3-isobutylidene-6-methyl piperazine-2,5-dione (5) have been isolated from the coral derived endophytic bacteria Brevibacterium sp. L-4 collected from the South China Sea. Their structures were elucidated through spectroscopic techniques including NMR (1D and 2D), MS, and EA, and their relative configurations were also assigned by NMR analysis...
2016: Natural Product Research
https://www.readbyqxmd.com/read/26125201/structural-requirements-for-cns-active-opioid-glycopeptides
#17
Mark Lefever, Yingxue Li, Bobbi Anglin, Dhanasekaran Muthu, Denise Giuvelis, John J Lowery, Brian I Knapp, Jean M Bidlack, Edward J Bilsky, Robin Polt
Glycopeptides related to β-endorphin penetrate the blood-brain barrier (BBB) of mice to produce antinociception. Two series of glycopeptides were assessed for opioid receptor binding affinity. Attempts to alter the mu-selectivity of [D-Ala(2),N-MePhe(4),Gly-ol(5)]enkephalin (DAMGO)-related glycopeptides by altering the charged residues of the amphipathic helical address were unsuccessful. A series of pan-agonists was evaluated for antinociceptive activity (55 °C tail flick) in mice. A flexible linker was required to maintain antinociceptive activity...
August 13, 2015: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/26104258/altered-metabolic-profile-in-early-and-late-onset-preeclampsia-an-ftir-spectroscopic-study
#18
Rashmi Mukherjee, Chaitali Datta Ray, Sabyasachi Ray, Swagata Dasgupta, Koel Chaudhury
OBJECTIVE: Metabolic anomalies, if any, between early and late onset preeclampsia [PE] were explored using Fourier transform infrared [FTIR] spectroscopy. SETTING: Department of Gynecology and Obstetrics, SSKM Hospital, IPGMER, Kolkata and Midnapur Medical College Hospital, Midnapur, India. SAMPLE: 80 pregnant women attending routine antenatal care units; (i) early onset PE [gestational age; GA<34weeks] (ii) late onset PE [GA>34weeks] (iii) early onset control [GA 24-34weeks] and (iv) late onset control [GA>34weeks]...
January 2014: Pregnancy Hypertension
https://www.readbyqxmd.com/read/25975031/-comparison-of-chemical-composition-between-raw-and-vinegar-baked-paeoniae-radix-alba-using-nmr-based-metabolomic-approach
#19
COMPARATIVE STUDY
Zhen-Yu Li, Ma-Li Fan, Xue-Mei Qin
To compare the chemical change of Paeoniae Radix Alba (PRA) after vinegar-baking processing, as well as the effect of vinegar types exerted on the processing, 1H NMR-based metabolomic approach combined with multivariate statistical analysis was used to investigate the different metabolites between the raw and two vinegar-baked PRA. More than thirty metabolites were identified in the 1H NMR spectrum of PRA, and the multivariate statistical analysis showed that raw and two vinegar-baked PRA could be separated obviously...
February 2015: Yao Xue Xue Bao, Acta Pharmaceutica Sinica
https://www.readbyqxmd.com/read/25956673/in-vitro-leishmanicidal-activity-of-1-3-disubstituted-5-nitroindazoles
#20
Clotilde Marín, Inmaculada Ramírez-Macías, María José Rosales, Beatriz Muro, Felipe Reviriego, Pilar Navarro, Vicente J Arán, Manuel Sánchez-Moreno
The antiprotozoal activity of some indazole-derived amines (2, 3, 5-8) as well as that of some simple structurally related 3-alkoxy-1-alkyl-5-nitroindazoles (1, 4) against promastigote and amastigote forms of Leishmania infantum and Leishmania braziliensis is reported. In some cases, these compounds showed in vitro activities against the different morphological forms of Leishmania similar to or higher than those of the reference drug glucantime; this fact, along with low unspecific cytotoxicities against macrophages shown by some of them, led to good selectivity indexes (SI)...
August 2015: Acta Tropica
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