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Updated: Jul 11, 2025

Extraction of Non-Protein Amino Acids from Cyanobacteria for Liquid Chromatography-Tandem Mass Spectrometry Analysis
Published on: December 9, 2022
Occurrence of D-amino acids in natural products
Daniel W Armstrong1, Alain Berthod2
1Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, 76019, USA. sec4dwa@uta.edu.
Abstract:
Since the identified standard genetic code contains 61 triplet codons of three bases for the 20 L-proteinogenic amino acids (AAs), no D-AA should be found in natural products. This is not what is observed in the living world. D-AAs are found in numerous natural compounds produced by bacteria, algae, fungi, or marine animals, and even vertebrates. A review of the literature indicated the existence of at least 132 peptide natural compounds in which D-AAs are an essential part of their structure. All compounds are listed, numbered and described herein. The two biosynthetic routes leading to the presence of D-AA in natural products are: non-ribosomal peptide synthesis (NRPS), and ribosomally synthesized and post-translationally modified peptide (RiPP) synthesis which are described. The methods used to identify the AA chirality within naturally occurring peptides are briefly discussed. The biological activity of an all-L synthetic peptide is most often completely different from that of the D-containing natural compounds. Analyzing the selected natural compounds showed that D-Ala, D-Val, D-Leu and D-Ser are the most commonly encountered D-AAs closely followed by the non-proteinogenic D-allo-Thr. D-Lys and D-Met were the least prevalent D-AAs in naturally occurring compounds.
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