Issue 43, 2023

Biocatalytic reductive amination as a route to isotopically labelled amino acids suitable for analysis of large proteins by NMR

Abstract

We demonstrate an atom-efficient and easy to use H2-driven biocatalytic platform for the enantioselective incorporation of 2H-atoms into amino acids. By combining the biocatalytic deuteration catalyst with amino acid dehydrogenase enzymes capable of reductive amination, we synthesised a library of multiply isotopically labelled amino acids from low-cost isotopic precursors, such as 2H2O and 15NH4+. The chosen approach avoids the use of pre-labeled 2H-reducing agents, and therefore vastly simplifies product cleanup. Notably, this strategy enables 2H, 15N, and an asymmetric centre to be introduced at a molecular site in a single step, with full selectivity, under benign conditions, and with near 100% atom economy. The method facilitates the preparation of amino acid isotopologues on a half-gram scale. These amino acids have wide applicability in the analytical life sciences, and in particular for NMR spectroscopic analysis of proteins. To demonstrate the benefits of the approach for enabling the workflow of protein NMR chemists, we prepared L-[α-2H,15N, β-13C]-alanine and integrated it into a large (>400 kDa) heat-shock protein oligomer, which was subsequently analysable by methyl-TROSY techniques, revealing new structural information.

Graphical abstract: Biocatalytic reductive amination as a route to isotopically labelled amino acids suitable for analysis of large proteins by NMR

Supplementary files

Article information

Article type
Edge Article
Submitted
03 Apr 2023
Accepted
20 Sep 2023
First published
26 Oct 2023
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2023,14, 12160-12165

Biocatalytic reductive amination as a route to isotopically labelled amino acids suitable for analysis of large proteins by NMR

J. S. Rowbotham, J. H. Nicholson, M. A. Ramirez, K. Urata, P. M. T. Todd, G. Karunanithy, L. Lauterbach, H. A. Reeve, A. J. Baldwin and K. A. Vincent, Chem. Sci., 2023, 14, 12160 DOI: 10.1039/D3SC01718D

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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