NMR analysis: potential and challenges as a homeopathic basic research tool

Homeopathic ultra-diluted solutions surpass the threshold of matter dispersion and, consequently, their chemical constitution is similar to inert solvent. Nevertheless, randomized clinical trials have shown that the clinical effects of these homeopathic medicines are superior to placebo1. Nuclear magnetic resonance (NMR) is one of the most promising techniques to detect physicochemical alterations induced by homeopathic procedures2,3. Aims: To investigate T2 NMR relaxation times of Zincum metallicumand lactose dynamized samples. Methodology: Zincum metallicumsamples were ground until 6dH using lactose as an excipient. Subsequently, these samples were dynamized with ultrapure water to produce 8dH, 9dH, 10dH,and 11dH. Lactose dynamized samples (6dH-11dH) were used as control. Aliquots of 540µl of each sample were diluted with 60µl of deuterated water (D2O) in 5mm tubes. The analyses were carried out in Bruker Ascend TM 500MHZ spectrometer at 288 K. Results and discussion: The Zincum metallicumand lactose T2 relaxation times were very similar, except for Zincum metallicum8dH, which presented a value of 1.226 in comparison to 1.036 of lactose 8dH. The following T2 values were registered: 1.287 -9dH; 1.413 -10dH; 1.467 -11dH, and 1.303 -9dH; 1.400 ­10dH; 1.350 -11dH, for Zincum metallicumand lactose, respectively. The differences detected in 8dH samples are probably due to the presence of lactose in the first dilution step, in which 1 part of the 6dH triturated mixture was diluted in 9 parts of water, to prepare 7dH. Following this homeopathic procedure, 8dH solutions remain around 1% of lactose which could be influenced by the T2 values registered.Conclusion: These preliminary results showed the possibility to apply the NMR technique to evaluate the influence of dynamization in the relaxation parameters. Further studies should be carried out with other potencies and/or other homeopathic substances, in addition to the evaluation of T1 and the T1/T2 parameters, as previously described by other groups.

Structural basis for cross-reactivity and conformation fluctuation of the major beech pollen allergen Fag s 1.

Fag s 1 is a member of the Pathogen Related protein family 10 (PR-10) and can elicit cross-reaction with IgE antibodies produced against the birch pollen allergen Bet v 1. The Nuclear Magnetic Resonance (NMR) structure of Fag s 1 is presented along with its dynamic properties. It shares 66% identity with Bet v 1 and exhibits the expected three α-helices and seven ß-sheets arranged as a semi-beta barrel and exposing the residues mapped as the Bet v 1 IgE epitope. The structural dynamics of Fag s 1 were monitored on the fast and intermediate timescales, using relaxation rates. The complex dynamics of Fag s 1 are closely related to the internal cavity, and they modulate IgE and ligand binding.

Hydration and conformational equilibrium in yeast thioredoxin 1: implication for H(+) exchange.

One of the ancestral features of thioredoxins is the presence of a water cavity. Here, we report that a largely hydrated, conserved, buried aspartic acid in the water cavity modulates the dynamics of the interacting loops of yeast thioredoxin 1 (yTrx1). It is well-established that the aspartic acid, Asp24 for yTrx1, works as a proton acceptor in the reduction of the target protein. We propose a complementary role for Asp24 of coupling hydration and conformational motion of the water cavity and interacting loops. The intimate contact between the water cavity and the interacting loops means that motion at the water cavity will affect the interacting loops and vice versa. The D24N mutation alters the conformational equilibrium for both the oxidized and reduced states, quenching the conformational motion in the water cavity. By measuring the hydration and molecular dynamics simulation of wild-type yTrx1 and the D24N mutant, we showed that Asn24 is more exposed to water than Asp24 and the water cavity is smaller in the mutant, closing the inner part of the water cavity. We discuss how the conformational equilibrium contributes to the mechanism of catalysis and H(+) exchange.

Mapping the interactions between a major pollen allergen and human IgE antibodies.

The interaction of specific IgE antibodies with allergens is a key event in the induction of allergic symptoms, thus representing an important target for therapeutic interventions in Type I allergies. We report here the solution NMR structure of Art v 1, the major mugwort pollen allergen. Art v 1 is the first protein structure with an allergenic defensin fold linked to a polyproline domain, which has not been identified in any reported allergen structure in the PDB. Moreover, the direct interaction of polyclonal IgE antibodies from an allergic patient has been mapped on the surface of an allergen for the first time. The data presented herein provide the basis for the design of tools for safe and effective vaccination against mugwort pollen allergy.

Sequence-specific 1H, 15N and 13C resonance assignments of Art v 1: a proline-rich allergen of Artemisia vulgaris pollen.

Art v 1 is the major allergen of Artemisia vulgaris. The IgE raised against Art v 1 not only can cross-react with other proteins from the Asteraceae family members but also with components of various forms of food. Art v 1 is an important target for immunotherapy strategies, including vaccination with hypoallergenic derivatives or chimeras. We report the (1)H, (13)C, and (15)N resonance assignments of the recombinant Art v 1 and identification of secondary structures based on (13)C chemical shifts.

A new bioactive steroidal saponin from Sansevieria cylindrica.

A new steroidal saponin was isolated from the leaves of Sansevieria cylindrica. Its structure was established as (3beta,12beta,15alpha,25S)-26-(beta-D-glucopyranosyloxy)-22-hydroxyfurost-5-en-3-yl 12-O- (6-deoxy-alpha-L-mannopyranosyl)-15-O-(6-deoxy-alpha-L-mannopyranosyl)-beta-D-glucopyranoside. The structural identification was performed using detailed analyses of (1)H and (13)C NMR spectra including 2D NMR spectroscopic techniques (COSY, HETCOR, HMBC and HMQC) and chemical conversions. The steroidal saponin showed no haemolytic effects in the in vitro assays and demonstrated inhibition of the capillary permeability activity.