Artigos científicos, teses e dissertações
Publicados nas melhores instituições de ensino

We demonstrate an experimental approach to structural studies of unfolded and partially folded proteins in which conformational distributions are probed at a site-specific level by 2D solid-state 13C NMR spectroscopy of glassy frozen solutions. Experiments on chemical denaturatio...

Otherwise unavailable information concerning the distribution of phosphorylated compounds in biological systems is obtained by a combined solid-state/solution-state NMR approach, illustrated here for oocytes from Rana pipiens. General methodology is developed, and further extensi...

Complete resolution of the amide resonances in a three-dimensional solid-state NMR correlation spectrum of a uniformly 15N-labeled membrane protein in oriented phospholipid bilayers is demonstrated. The three orientationally dependent frequencies, 1H chemical shift, 1H–15N dipola...

Solid-state cross-polarization/magic-angle sample-spinning 13C NMR spectra have been recorded on chlorophyll a-water aggregates, methyl pyrochlorophyllide a, and methyl pyropheophorbide a (derivatives that lack a phytyl chain). Spectra have also been collected under a decoupling ...

We have performed solid-state 31P-19F REDOR nuclear magnetic resonance (NMR) experiments to monitor changes in minor groove width of the oligonucleotide d(CGCAAA2′FUTGGC)·d(GCCAAT(pS)TT GCG) (A3T2) upon binding of the drug distamycin A at different stoichiometries. In the hydrate...

Approximately 80-90 % of the drugs on the market are available in solid form, sold as tablets and capsules containing product in a powdered form. A frequent problem associated to the drugs in the solid state is the low rate of dissolution, especially in aqueous medium or in polar...

2010...

The motions of the aromatic amino acids of the fd bacteriophage coat protein are described by solid-state 2H, 13C, and 15N NMR. Tryptophan-26 is immobile on time scales as slow as 10(3) HZ. The phenylalanine and tyrosine rings undergo 180 degree flips about the C beta--C gamma bo...

After the huge development occurred during the last 30 years, including the proposition of methods such as magic-angle spinning, multiple-resonance experiments (cross-polarization, high-power decoupling, etc.), multiple-pulses techniques, multiple quantum experiments, and multidi...

We report molecular dynamics simulations in the explicit membrane environment of a small membrane-embedded protein, sarcolipin, which regulates the sarcoplasmic reticulum Ca-ATPase activity in both cardiac and skeletal muscle. In its monomeric form, we found that sarcolipin adopt...

31P cross polarization (CP) magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra were acquired for various linear and branched di- and tri-nucleotides attached to a controlled pore glass (CPG) solid support. The technique readily distinguishes the oxidation state o...

High-resolution orientational constraints from solid-state NMR spectroscopy of uniformly aligned biological macromolecules provide a great structural analysis problem. Several approaches to this problem have been made in the past. Here a vector algebra method is developed that pr...

The objective of this work is physicochemical characterization of nimesulide-cyclodextrin binary systems both in solution and solid state and to improve the dissolution properties of nimesulide (N) via complexation with α-, β, and γ-cyclodextrins (CDs). Detection of inclusion com...

The monovalent cation selective channel formed by a dimer of the polypeptide gramicidin A has a single-stranded, right-handed helical motif with 6.5 residues per turn forming a 4-Å diameter pore. The structure has been refined to high resolution against 120 orientational constrai...

The atomic resolution structure of fd coat protein determined by solid-state NMR spectroscopy of magnetically aligned filamentous bacteriophage particles differs from that previously determined by x-ray fiber diffraction. Most notably, the 50-residue protein is not a single cu...

2010...

We report the observation of high-resolution solid-state NMR spectra of 23Na (I = [unk]), 27Al (I = [unk]) and 51V (I = [unk]) in various inorganic systems. We show that, contrary to popular belief, relatively high-resolution (≈10 ppm linewidth) spectra may be obtained from quadr...

Complexation between acyclovir (ACV), an antiviral drug used for the treatment of herpes simplex virus infection, and beta-cyclodextrin (beta-CD) was studied in solution and in solid states. Complexation in solution was evaluated using solubility studies and nuclear magnetic reso...

Solid-state NMR spectra of natural abundance 13C in reaction centers from photosynthetic bacteria Rhodobacter sphaeroides R-26 was measured. When the quinone acceptors were removed and continuous visible illumination of the sample was provided, exceptionally strong nuclear spin p...

We introduce an analytical method that combines in one pot the advantages of column chromatography separation and NMR structural analysis. The separation of the NMR spectra of the components of a mixture can be achieved according to their apparent diffusion rates [James, T. L....

The location of the main binding site for sodium in the gramicidin A (GA) channel was investigated with molecular dynamics simulations, using an atomic model of the channel embedded in a fully hydrated dimyristoyl phosphatidycholine (DMPC) bilayer. Twenty-four separate simulation...