Synthesis of Isotopically Labeled α‐Amino Acids

Reid, Caroline M.; Sutherland, Andrew

doi:10.1002/9783527631766.ch11

Cited by 5 publications

(4 citation statements)

References 109 publications

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“…[2,3] A possible way to address some of the key questions regarding the structure and functional properties of peptides and proteins, is to prepare them in an isotopically labeled version, starting from amino acids labeled in stable isotopes, such as 2 H, 13 C, 15 N, or 17 O/ 18 O. [4] Such labeled species have been involved in many studies where both qualitative and/or quantitative information were extracted from MS, [5] IR [6] or NMR analyses. [7] Producing peptides/proteins labeled in 17 O/ 18 O is particularly interesting, with oxygen atoms being frequently involved in hydrogen bonds stabilizing complex macromolecular protein structures.…”

Section: Introductionmentioning

confidence: 99%

Fast and Cost‐Efficient ¹⁷O‐Isotopic Labeling of Carboxylic Groups in Biomolecules: From Free Amino Acids to Peptide Chains

Špačková

Goldberga

Yadav

et al. 2023

Chemistry A European J

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17O NMR spectroscopy is a powerful technique, which can provide unique information regarding the structure and reactivity of biomolecules. However, the low natural abundance of 17O (0.04 %) generally requires working with enriched samples, which are not easily accessible. Here, we present simple, fast and cost‐efficient 17O‐enrichment strategies for amino acids and peptides by using mechanochemistry. First, five unprotected amino acids were enriched under ambient conditions, consuming only microliter amounts of costly labeled water, and producing pure molecules with enrichment levels up to ∼40 %, yields ∼60‐85 %, and no loss of optical purity. Subsequently, 17O‐enriched Fmoc/tBu‐protected amino acids were produced on a 1 g/day scale with high enrichment levels. Lastly, a site‐selective 17O‐labeling of carboxylic functions in peptide side‐chains was achieved for RGD and GRGDS peptides, with ∼28 % enrichment level. For all molecules, 17O ssNMR spectra were recorded at 14.1 T in reasonable times, making this an important step forward for future NMR studies of biomolecules.

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Section: Introductionmentioning

confidence: 99%

Fast and Cost‐Efficient ¹⁷O‐Isotopic Labeling of Carboxylic Groups in Biomolecules: From Free Amino Acids to Peptide Chains

Špačková

Goldberga

Yadav

et al. 2023

Chemistry A European J

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show abstract

Section: Introductionmentioning

confidence: 99%

Fast and cost-efficient approaches for 17O-isotopic labeling of carboxylic groups in biomolecules: from free amino acids to peptide chains

Špačková

Goldberga

Yadav

et al. 2022

Preprint

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17O NMR spectroscopy is a powerful analytical technique, which enables to access unique information regarding the structure and reactivity of biomolecules, such as peptides and proteins. However, due to the exceedingly low natural abundance of 17O (0.04 %), it is necessary to work with 17O-enriched samples, which are not easily accessible because of the experimental constraints and high costs associated with the traditional enrichment procedures. Here, we present simple, fast and cost-efficient labeling strategies for 17O-enrichment of amino acids and peptides. First, using mechanochemical saponification, a variety of unprotected amino acids were enriched within 30 min of milling under ambient conditions, consuming only microliter amounts of costly labeled water, and producing pure molecules with high enrichment levels (up to ~ 40 %), and in medium to high yields (~ 60 - 85 %) without the loss of their optical purity (ee > 99%). The labeling efficiency of the mechanochemical protocol was then compared to a re-optimised enrichment strategy based on acid-catalysed oxygen exchange. Subsequently, 17O-enriched Fmoc/tBu-protected amino acids were produced on a 1 g/day scale with high enrichment levels (~ 40 %), and in high synthetic yields (~ 75 - 85 %), by scaling up the mechanochemical enrichment followed by a Fmoc-protection step. Lastly, a direct site-selective 17O-labeling of carboxylic functions in peptide side-chains was developed and applied to the RGD and GRGDS peptides, reaching up to 29% enrichment level. Producing highly enriched molecules enabled to record 17O solid-state NMR spectra at 14.1 T in reasonable analytical times. Overall, this work represents an important step forward in providing easy access to highly 17O-enriched peptides and proteins to be subsequently studied by high-resolution 17O NMR spectroscopy.

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“…Known L -α-amino acids labeled with stable isotopes at specific positions have been reported [23,24]. Synthetic methods are optimized to resolve problems due to diastereotopic methyl groups, hydrogen atoms and additional chiral centers.…”

Section: Introductionmentioning

confidence: 99%

Access to Any Site Directed Stable Isotope (2H, 13C, 15N, 17O and 18O) in Genetically Encoded Amino Acids

Dawadi

Lugtenburg

2013

Molecules

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Proteins and peptides play a preeminent role in the processes of living cells. The only way to study structure-function relationships of a protein at the atomic level without any perturbation is by using non-invasive isotope sensitive techniques with site-directed stable isotope incorporation at a predetermined amino acid residue in the protein chain. The method can be extended to study the protein chain tagged with stable isotope enriched amino acid residues at any position or combinations of positions in the system. In order to access these studies synthetic methods to prepare any possible isotopologue and isotopomer of the 22 genetically encoded amino acids have to be available. In this paper the synthetic schemes and the stable isotope enriched building blocks that are available via commercially available stable isotope enriched starting materials are described.

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Synthesis of Isotopically Labeled α‐Amino Acids

Cited by 5 publications

References 109 publications

Fast and Cost‐Efficient ¹⁷O‐Isotopic Labeling of Carboxylic Groups in Biomolecules: From Free Amino Acids to Peptide Chains

Fast and Cost‐Efficient ¹⁷O‐Isotopic Labeling of Carboxylic Groups in Biomolecules: From Free Amino Acids to Peptide Chains

Fast and cost-efficient approaches for 17O-isotopic labeling of carboxylic groups in biomolecules: from free amino acids to peptide chains

Access to Any Site Directed Stable Isotope (2H, 13C, 15N, 17O and 18O) in Genetically Encoded Amino Acids

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Synthesis of Isotopically Labeled α‐Amino Acids

Cited by 5 publications

References 109 publications

Fast and Cost‐Efficient 17O‐Isotopic Labeling of Carboxylic Groups in Biomolecules: From Free Amino Acids to Peptide Chains

Fast and Cost‐Efficient 17O‐Isotopic Labeling of Carboxylic Groups in Biomolecules: From Free Amino Acids to Peptide Chains

Fast and cost-efficient approaches for 17O-isotopic labeling of carboxylic groups in biomolecules: from free amino acids to peptide chains

Access to Any Site Directed Stable Isotope (2H, 13C, 15N, 17O and 18O) in Genetically Encoded Amino Acids

Contact Info

Product

Resources

About

Fast and Cost‐Efficient ¹⁷O‐Isotopic Labeling of Carboxylic Groups in Biomolecules: From Free Amino Acids to Peptide Chains

Fast and Cost‐Efficient ¹⁷O‐Isotopic Labeling of Carboxylic Groups in Biomolecules: From Free Amino Acids to Peptide Chains