PXD066785-1

PXD066785 is an original dataset announced via ProteomeXchange.

Title	Mechanism of installing multiple oxazolone/thioamide pairs on a ubiquitous family of copper-chelating proteins in oxidative stress defense
Description	Ribosomally synthesized and post‑translationally modified peptides (RiPPs) constitute a structurally diverse class of natural products with wide‑ranging bioactivities. Multinuclear non‑heme iron‑dependent oxidases (MNIOs) have recently emerged as important enzymes expanding the types of post-translational modifications (PTM) of RiPPs. Here we characterize two MNIO‑modified small proteins from Pseudomonas protegens Pf‑5, designated pseudoprobactin 1 and 2. Mass spectrometry and NMR spectroscopy revealed that their precursor proteins, PbnA1 and PbnA2, contain an N-terminal signal peptide and an intramolecular disulfide bond between the N-terminal and C-terminal cysteines. The remaining cysteine residues undergo MNIO-mediated modification into oxazolone/thioamide pairs, catalyzed by the PbnB1C1/PbnB2C2 enzyme complex. While the signal peptide and disulfide bond are dispensable for modification, the residues immediately downstream of the cysteines in the precursor proteins critically influence PbnB1C1/PbnB2C2 activity, with PbnB2C2 exhibiting a specific order in modifying multiple cysteine residues. Functional assays demonstrate that pseudoprobactin 1 and 2 bind copper with high specificity and enhance Pf-5 survival under chlorite-induced oxidative stress. Combined with our bioinformatic analysis, these findings establish oxazolone/thioamide as a prevalent MNIO-mediated modification, define the substrate recognition determinants, and reveal a previously unrecognized role for MNIO-modified small proteins in bacterial oxidative stress defense.
HostingRepository	PRIDE
AnnounceDate	2026-07-29
AnnouncementXML	Submission_2026-07-29_01:41:44.710.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	hanzhong feng
SpeciesList	scientific name: Pseudomonas protegens Pf-5; NCBI TaxID: NEWT:220664; scientific name: Bacteria; NCBI TaxID: NCBITaxon:2;
ModificationList	iodoacetamide derivatized residue
Instrument	Orbitrap Exploris 480

Revision	Datetime	Status	ChangeLog Entry
0	2025-07-30 17:48:55	ID requested
⏵ 1	2026-07-29 01:41:45	announced

Dataset with its publication pending

submitter keyword: MNIO ,metallophore,chlorite,RiPP

Yong-Xing He
contact affiliation	Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
contact email	heyx@lzu.edu.cn
lab head
hanzhong feng
contact affiliation	Lanzhou University
contact email	fenghzh19@lzu.edu.cn
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD066785
     1. Label: PRIDE project
     2. Name: Mechanism of installing multiple oxazolone/thioamide pairs on a ubiquitous family of copper-chelating proteins in oxidative stress defense