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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
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Unexpected Transformations during Pyrroloiminoquinone Biosynthesis.
Josseline Ramos Figueroa1, Lingyang Zhu1, Wilfred A van der Donk1
1Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
Journal of the American Chemical Society
|May 8, 2024
Summary
The biosynthesis of pyrroloiminoquinones is more complex than previously thought. This study reveals amino groups are incorporated from glycine, asparagine, and leucine via tRNA-dependent pathways, challenging earlier proposed routes.
Area of Science:
- Natural Product Biosynthesis
- Enzymology
- Molecular Evolution
Background:
- Pyrroloiminoquinones are biologically active natural products derived from tryptophan.
- Their biosynthetic pathways have been largely unknown.
- Previous studies identified a PEptide Aminoacyl-tRNA Ligase (PEARL) initiating ammosamide synthesis via tryptophan attachment.
Purpose of the Study:
- To elucidate the complex biosynthetic pathway of pyrroloiminoquinones.
- To identify the sources of amino groups incorporated into these compounds.
- To investigate the evolutionary origins of key enzymes in the pathway.
Main Methods:
- Analysis of four additional enzymes from two gene clusters.
- Investigating tRNA-dependent amino group incorporation.
- Biochemical characterization of an FAD-dependent glycine oxidase (Amm14) and a quinone reductase.
Main Results:
- The previously proposed biosynthetic pathway for ammosamides was found to be incorrect.
- Amino groups in pyrroloiminoquinones originate from glycine, asparagine, and leucine, incorporated via tRNA-dependent mechanisms.
- Amm14 and a quinone reductase are crucial for incorporating nitrogens from glycine, leucine, and asparagine, respectively.
Conclusions:
- Nature's route to pyrroloiminoquinones is significantly more intricate than anticipated.
- Multiple amino acid sources and tRNA-dependent mechanisms are involved in their biosynthesis.
- PEARLs and related enzymes likely evolved from the ATP-GRASP protein family.
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