Late-Stage Posttranslational Assembly of Fosfazinomycins
- 1University of Illinois at Urbana-Champaign
Abstract
The fosfazinomycins are phosphonate natural products with antifungal activity. Their main scaffold is composed of a phosphonate moiety attached to the carboxylate of arginine via a hydrazine linkage. Previous studies have elucidated a convergent biosynthetic pathway that independently assembles phosphonate and hydrazine synthons, but how these building blocks are then connected could not be determined. In this work, we provide the final missing steps in fosfazinomycin biosynthesis by revealing an unexpected engagement of biosynthetic machinery that is typically involved in ribosomally synthesized and post-translationally modified peptides (RiPPs). An asparagine synthetase-like (AS-like) enzyme catalyzes the installation of hydrazine onto the carboxylate of Arg at the C-terminus of a short ribosomally synthesized precursor peptide. The terminal nitrogen of the resulting peptide hydrazide is methylated, and the phosphonate moiety is activated to a triphosphate-like intermediate through two separate kinase catalyzed phosphorylation steps. A nucleotidyl transferase then catalyzes the ligation of the two fragments to generate the mature fosfazinomycin scaffold on a peptide. Aminopeptidase cleavage of this peptide then yields fosfazinomycin B (fosB), which serves as substrate for a valinyl-tRNA dependent reaction to afford fosfazinomycin A (fosA). This work demonstrates an unprecedented example of the convergence of RiPP and phosphonate biosynthetic logic, an enzymatic route to peptide hydrazides that are widely used in peptide ligation chemistry, and an unusual activation sequence for conjugation of phosphonates.
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BibTeX
@misc{cha2026latestage,
title = {{Late-Stage Posttranslational Assembly of Fosfazinomycins}},
author = {L. Cha and Z. Huang and C. Padhi and K.-K. A. Wang and W. van der Donk},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.23.753898},
url = {https://www.biorxiv.org/content/10.64898/2026.09.23.753898v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Late-Stage Posttranslational Assembly of Fosfazinomycins
AU - L. Cha
AU - Z. Huang
AU - C. Padhi
AU - K.-K. A. Wang
AU - W. van der Donk
PY - 2026
DA - 2026/09/23
PB - bioRxiv
DO - 10.64898/2026.09.23.753898
UR - https://www.biorxiv.org/content/10.64898/2026.09.23.753898v1
AB - The fosfazinomycins are phosphonate natural products with antifungal activity. Their main scaffold is composed of a phosphonate moiety attached to the carboxylate of arginine via a hydrazine linkage. Previous studies have elucidated a convergent biosynthetic pathway that independently assembles phosphonate and hydrazine synthons, but how these building blocks are then connected could not be determined. In this work, we provide the final missing steps in fosfazinomycin biosynthesis by revealing an unexpected engagement of biosynthetic machinery that is typically involved in ribosomally synthesized and post-translationally modified peptides (RiPPs). An asparagine synthetase-like (AS-like) enzyme catalyzes the installation of hydrazine onto the carboxylate of Arg at the C-terminus of a short ribosomally synthesized precursor peptide. The terminal nitrogen of the resulting peptide hydrazide is methylated, and the phosphonate moiety is activated to a triphosphate-like intermediate through two separate kinase catalyzed phosphorylation steps. A nucleotidyl transferase then catalyzes the ligation of the two fragments to generate the mature fosfazinomycin scaffold on a peptide. Aminopeptidase cleavage of this peptide then yields fosfazinomycin B (fosB), which serves as substrate for a valinyl-tRNA dependent reaction to afford fosfazinomycin A (fosA). This work demonstrates an unprecedented example of the convergence of RiPP and phosphonate biosynthetic logic, an enzymatic route to peptide hydrazides that are widely used in peptide ligation chemistry, and an unusual activation sequence for conjugation of phosphonates.
ER -