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Updated: May 14, 2026

13C6-Glucose Labeling Associated with LC-MS: Identification of Plant Primary Organs in Secondary Metabolite Synthesis
Published on: March 22, 2024
A straightforward method for stereospecific assignment of val and leu prochiral methyl groups by solid-state NMR:
Guohua Lv1, Hannes Klaus Faßhuber, Antoine Loquet
1Max Planck Institute for Biophysical Chemistry, Department of NMR-based Structural Biology, Am Fassberg 11, 37077 Göttingen, Germany.
Abstract:
The unambiguous stereospecific assignment of the prochiral methyl groups in Val and Leu plays an important role in the structural investigation of proteins by NMR. Here, we present a straightforward method for their stereospecific solid-state NMR assignment based on [2-(13)C]Glucose ([2-(13)C]Glc) as the sole carbon source during protein expression. The approach is fundamentally based on the stereo-selective biosynthetic pathway of Val and Leu, and the co-presence of [2-(13)C]pyruvate produced mainly by glycolysis and [3-(13)C]/[1,3-(13)C]pyruvate most probably formed through scrambling in the pentose phosphate pathway. As a consequence, the isotope spin pairs (13)Cβ-(13)Cγ2 and (13)Cα-(13)Cγ1 in Val, and (13)Cγ-(13)Cδ2 and (13)Cβ-(13)Cδ1 in Leu are obtained. The approach is successfully demonstrated with the stereospecific assignment of the methyl groups of Val and Leu of type 3 secretion system PrgI needles and microcrystalline ubiquitin.
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