NMR Spectroscopy

Red Glead Discovery (RGD) offers high-quality solution NMR services, ranging from quality control to advanced structure elucidation. We have strong problem-solving skills and experience in NMR studies of small molecules, biomolecules and polymers – in academic research as well as in industrial drug discovery settings.

Why choose us

Our NMR team is focused on structural analysis and quantifications of organic molecules, natural products, and peptides, but also conducts studies of polysaccharides, proteins and polymers. Our expertise in combination with fit-for-purpose NMR methodologies enable tailored study packages and delivery of high-quality study reports.

Structure ID (metabolites, impurities, by-products) or purity assays are common approaches. Peptide NMR is another specialty of ours, including verification of primary peptide structure (i.e. peptide sequencing) and secondary structure characterisation. Diagnostics of 3D conformation and conformational dynamics are evaluated for peptides and proteins, including analysis of protein-protein interactions. Further, NMR is applied for fragment screening and studies of ligand-protein interactions.

Our in-house NMR spectrometer park provides a high capacity for taking on tasks on an ad hoc basis and finding optimized solutions for each given case. Our instrumentation covers a wide range of different nuclei (e.g. 1H, 2H, 3H, 11B, 13C, 15N, 19F, 29Si, 31P, 95Mo) and a wide selection of NMR experiments are available.
A quality system for quantitative and qualitative NMR has been in place since 2016, to further support our development phase clients.

NMR Spectroscopy & Integrated drug discovery

NMR data on all produced molecules is a cornerstone of our basic QC package together with HPLC-UV and HPLC-MS. The NMR technique also serves as an important support to our medicinal chemistry synthesis teams, by e.g. QC of starting materials, identification of by-products and detection of racemisations.

In fragment-based lead discovery (FBLD) at RGD, ligand-detected 1D 1H/19F NMR is an important method for fragment screening, used either as a stand-alone technique or to provide orthogonal output to e.g. WAC, DSF and/or X-ray crystallography data. In this aspect, NMR also serves as a quality control of purity and identity for the fragment library.

Case 1

In 2017 and 2020, on behalf of a Danish pharmaceutical company, RGD accomplished structural elucidation of a small molecule by-product, formed during the reaction conditions applied by the client. RGD could confirm the formation of an unknown species by stressing the reaction components in the NMR tube and, after purification with preparative HPLC, obtain a full atom-specific assignment and identification of the impurity from the collected 1D and 2D 1H/13C/15N NMR data. As a follow-up project, our medicinal chemistry team synthesized the compound using a different reaction pathway and the chemical structure was confirmed by its consistency in NMR data.

Case 2

Upon request from a US pharmaceutical company during 2018-2019, RGD performed an NMR-based analysis of a specified small molecule (Mw ~200) in samples of a peptide (Mw > 2000) by applying the so-called CPMG pulse sequence – a technique that utilizes the difference in the T2 relaxation times between molecules of different size to allow for detection and quantification of low-level small molecule impurities. In dialogue with the client, RGD could design and optimize a semi-quantitative method to meet the Client’s needs in terms of detection limits and generate an associated validation report.

Our Approach

1D and 2D NMR experiments can be used for structure characterisation on different levels of detail. Determination or verification of covalent structures are accomplished through atom-specific chemical shift assignments. For peptides, 2D structure can be evaluated using the established method of chemical shift index, and information on 3D conformation can be retrieved e.g. through structural mapping with HSQC fingerprint methods.

RGD performs quantitative analysis by 1H and 19F NMR measurements, with application of certified references used as internal or external standards, or determination of relative abundance of e.g. acetate counter ions. We also apply the 1D 1H CPMG method for e.g.analysis of small molecule impurities in peptide samples, by so-called T2-filtration.

Equipment

  • 400 MHz Varian Inova spectrometer used for open access (1H/13C)
  • 500 MHz Varian Inova spectrometer. 3 RF channels. Commonly equipped with a triple resonance probe (1H/13C/15N), but several probe heads are available
  • 500 MHz Bruker Avance (2019). 2 RF channels, single-axis pulsed field gradients, 5mm X-nuclei-optimized double resonance broad banded iProbe with BB range 19F – 199Hg and 17O – 109Ag

Access to ultra-high field NMR spectrometers (600-900 MHz) can be arranged through Swedish NMR Centre.