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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, USA.
Biorxiv : the Preprint Server for Biology
|April 1, 2024
Summary
The biosynthesis of pyrroloiminoquinones is more complex than previously thought. This study reveals amino groups are sourced from glycine, asparagine, and leucine via tRNA-dependent pathways, involving novel enzymes.
Area of Science:
- Biochemistry
- Natural Product Biosynthesis
- Molecular Biology
Background:
- Pyrroloiminoquinones are natural products with known biological activities, derived from tryptophan.
- Their biosynthetic pathways have been largely unelucidated, with previous hypotheses on ammosamide production.
- The initial step involves tryptophan attachment to a scaffold peptide by a PEptide Amino-acyl tRNA ligase (PEARL).
Approach:
- Investigated the function of four novel enzymes within the ammosamide biosynthetic gene cluster (BGC).
- Utilized biochemical assays to determine the source of amino groups incorporated into the pyrroloiminoquinone structure.
- Performed evolutionary analysis of PEARLs and related enzymes.
Key Points:
- Demonstrated that amino groups in pyrroloiminoquinones originate from glycine, asparagine, and leucine, incorporated via tRNA-dependent mechanisms.
- Identified an FAD-dependent glycine oxidase essential for incorporating nitrogens from glycine and leucine.
- Characterized a quinone reductase crucial for asparagine incorporation.
Conclusions:
- The biosynthetic pathway for pyrroloiminoquinones is significantly more intricate than previously proposed.
- Revealed novel enzymatic activities and substrate specificities in natural product biosynthesis.
- Traced the evolutionary origins of PEARLs and related enzymes to the ATP-GRASP protein family.
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