Six domoic acid related compounds from the red alga, Chondria armata, and domoic acid biosynthesis by the diatom, Pseudo-nitzschia multiseries.

Content Provider	Europe PMC
Author	Maeno, Yukari Kotaki, Yuichi Terada, Ryuta Cho, Yuko Konoki, Keiichi Yotsu-Yamashita, Mari
Abstract	Domoic acid (DA, 1), a potent neurotoxin that causes amnesic shellfish poisoning, has been found in diatoms and red algae. While biosynthetic pathway towards DA from geranyl diphosphate and L-glutamate has been previously proposed, its late stage is still unclear. Here, six novel DA related compounds, 7'-methyl-isodomoic acid A (2) and B (3), N-geranyl-L-glutamic acid (4), 7'-hydroxymethyl-isodomoic acid A (5) and B (6), and N-geranyl-3(R)-hydroxy-L-glutamic acid (7), were isolated from the red alga, Chondria armata, and their structures were determined. The compounds 4 and 7, linear compounds, are predictable as the precursors to form the DA pyrrolidine ring. The compounds 2 and 3 are thought as the cyclized products of 7; therefore, dehydration and electron transfer from the internal olefin of 7 is a possible mechanism for the pyrrolidine ring formation. One terminal methyl group of the side chain of 2 and 3 is predicted to be oxidized to hydroxymethyl (5, 6), and then to carboxylic acids, forming isodomoic acids A and B. Finally, the terminal olefin of isodomoic acid A would be isomerized to form DA. In addition, [15N, D]-labeled 4 was incorporated into DA using the diatom, Pseudo-nitzschia multiseries, demonstrating that 4 is the genuine precursor of DA.
Journal	Scientific Reports [Sci Rep]
Volume Number	8
DOI	10.1038/s41598-017-18651-w
PubMed Central reference number	PMC5762911
Issue Number	1
PubMed reference number	29321590
e-ISSN	20452322
Language	English
Publisher	Nature Publishing Group
Publisher Date	2018-01-10
Publisher Place	London
Access Restriction	Open
Content Type	Text
Resource Type	Article
Subject	Multidisciplinary