Carbon–Deuterium Rotational-Echo Double-Resonance NMR Spectroscopy of Lyophilized Aspartame Formulations

Luthra, Suman; Utz, Marcel; Gorman, Eric M.; Pikal, Michael J.; Munson, Eric J.; Lubach, Joseph W.

doi:10.1002/jps.22769

Cited by 7 publications

(3 citation statements)

References 44 publications

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“…To conduct this test, we used rotational echo double-resonance (REDOR) NMR spectroscopy, which measures the dipolar coupling between 13 C and 2 H nuclei. 13 C{ 2 H} REDOR is commonly used to probe protein-membrane interactions (31)(32)(33)(34). We found that leucine interacts with a hydrogen near the headgroup of decanoic acid but not at the end of the tail ( Fig.…”

Section: Resultsmentioning

confidence: 92%

Prebiotic amino acids bind to and stabilize prebiotic fatty acid membranes

Cornell

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Xue

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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The membranes of the first protocells on the early Earth were likely self-assembled from fatty acids. A major challenge in understanding how protocells could have arisen and withstood changes in their environment is that fatty acid membranes are unstable in solutions containing high concentrations of salt (such as would have been prevalent in early oceans) or divalent cations (which would have been required for RNA catalysis). To test whether the inclusion of amino acids addresses this problem, we coupled direct techniques of cryoelectron microscopy and fluorescence microscopy with techniques of NMR spectroscopy, centrifuge filtration assays, and turbidity measurements. We find that a set of unmodified, prebiotic amino acids binds to prebiotic fatty acid membranes and that a subset stabilizes membranes in the presence of salt and Mg2+. Furthermore, we find that final concentrations of the amino acids need not be high to cause these effects; membrane stabilization persists after dilution as would have occurred during the rehydration of dried or partially dried pools. In addition to providing a means to stabilize protocell membranes, our results address the challenge of explaining how proteins could have become colocalized with membranes. Amino acids are the building blocks of proteins, and our results are consistent with a positive feedback loop in which amino acids bound to self-assembled fatty acid membranes, resulting in membrane stabilization and leading to more binding in turn. High local concentrations of molecular building blocks at the surface of fatty acid membranes may have aided the eventual formation of proteins.

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Section: Resultsmentioning

confidence: 92%

Prebiotic amino acids bind to and stabilize prebiotic fatty acid membranes

Cornell

Black

Xue

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

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“…Solidstate NMR has been used to study the correlation between structural relaxation processes in such systems and the degradation kinetics of the pharmaceutical payload. [139][140][141] All these types of experiments could potentially benefit enormously from the use of micro-coils integrated with microfluidics. Increased spatial resolution, required to differentiate rheological velocity fields at the micrometer level, needs specially designed magnetic field gradients.…”

Section: Flow Rheology and Morphologymentioning

confidence: 99%

Microscale nuclear magnetic resonance: a tool for soft matter research

et al. 2012

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Nuclear magnetic resonance spectroscopy (NMR) and imaging (MRI) are important non-destructive investigative techniques for soft matter research. Continuous advancements have not only lead to more sensitive detection, and new applications, but have also enabled the shrinking of the detectable volume of sample, and a reduction in time needed to acquire a spectrum or image. At the same time, advances in microstructuring and on-chip laboratories have also continued unabated. In recent years these two broad areas have been productively joined into what we term micro nuclear magnetic resonance (mMR), an exciting development that includes miniaturized detectors and hyphenation with other laboratory techniques, for it opens up a range of new possibilities for the soft matter scientist. In this paper we review the available miniaturization technologies for NMR and MRI detection, and also suggest a way to compare the performance of the detectors. The paper also takes a close look at chiplaboratory augmented mMR, and applications within the broad soft matter area. The review aims to contribute to a better understanding of both the scientific potential and the actual limits of mMR tools in the various interdisciplinary soft matter research fields.

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“…The two‐dimensional X‐H HMQC spectra (X = 14 N, 13 C…) recorded using REDOR sequence enable estimation of heteronuclear distance associated with intra‐ or intermolecular interaction. Luthra et al studied the annealing‐induced local conformational alteration of aspartame in its lyophilized ASD with sucrose and with trehalose using 13 C‐ 2 H REDOR dephasing curves. The results demonstrated that annealing led to the increase of the internuclear distance between aspartame and excipient in aspartame–sucrose, whereas the same was minimally affected by annealing of aspartame–trehalose.…”

Section: Miscibility/molecular Interactions In Asd By Ss‐nmr Spectrosmentioning

confidence: 99%