PqqU (PA2289) is the primary PQQ transporter in Pseudomonas aeruginosa and links carbon metabolism to iron homeostasis
Abstract
Pseudomonas aeruginosa relies on the redox cofactor pyrroloquinoline quinone (PQQ) for efficient glucose and ethanol metabolism via periplasmic dehydrogenases (Gcd and ExaA). While PQQ biosynthesis is well-characterized, its uptake mechanisms remain unclear. Here, we identify PA2289 (PqqU), a TonB-dependent transporter, as the primary PQQ importer in P. aeruginosa. Growth assays with PQQ-deficient mutants (ΔpqqABCDEH) demonstrated that PqqU is the primary uptake system for exogenous PQQ, rescuing growth on glucose and ethanol. Genomic analysis across 210 P. aeruginosa and 263 Pseudomonas strains revealed high conservation of PQQ biosynthesis and utilization genes, while PqqU showed lower prevalence (47.7%) in the genus. Transcriptional analyses using fluorescent reporters and quantitative reverse transcription PCR demonstrated that PqqU expression remains unchanged in response to PQQ, varying carbon sources, or iron availability, suggesting constitutive regulation. Comparative proteomics between wild-type and ΔpqqABCDEH strains, cultured on glucose or ethanol, uncovered extensive proteomic shifts, underscoring P. aeruginosa’s metabolic adaptability. Additionally, PQQ-dependent metabolic pathways appear to indirectly influence iron homeostasis, most likely through environmental acidification. Together, these results emphasize the critical role of PqqU in PQQ uptake and its broader significance in shaping the metabolic and environmental versatility of Pseudomonas.
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BibTeX
@article{paschalidis2026pqqu,
title = {{PqqU (PA2289) is the primary PQQ transporter in Pseudomonas aeruginosa and links carbon metabolism to iron homeostasis}},
author = {Christos Paschalidis and Manon Ferry and Anne-Eloïse Revillot- -Schmidt and Françoise Hoegy and Gaëtan Mislin and Johana Chicher and Emmanuel Boutant and Isabelle Schalk and Olivier Cunrath},
journal = {FEMS Microbiology Letters},
year = {2026},
month = aug,
doi = {10.1093/femsle/fnag084},
url = {https://hal.science/hal-05735562v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - PqqU (PA2289) is the primary PQQ transporter in Pseudomonas aeruginosa and links carbon metabolism to iron homeostasis
AU - Christos Paschalidis
AU - Manon Ferry
AU - Anne-Eloïse Revillot- -Schmidt
AU - Françoise Hoegy
AU - Gaëtan Mislin
AU - Johana Chicher
AU - Emmanuel Boutant
AU - Isabelle Schalk
AU - Olivier Cunrath
PY - 2026
DA - 2026/08/07
JO - FEMS Microbiology Letters
DO - 10.1093/femsle/fnag084
UR - https://hal.science/hal-05735562v1
AB - Pseudomonas aeruginosa relies on the redox cofactor pyrroloquinoline quinone (PQQ) for efficient glucose and ethanol metabolism via periplasmic dehydrogenases (Gcd and ExaA). While PQQ biosynthesis is well-characterized, its uptake mechanisms remain unclear. Here, we identify PA2289 (PqqU), a TonB-dependent transporter, as the primary PQQ importer in P. aeruginosa. Growth assays with PQQ-deficient mutants (ΔpqqABCDEH) demonstrated that PqqU is the primary uptake system for exogenous PQQ, rescuing growth on glucose and ethanol. Genomic analysis across 210 P. aeruginosa and 263 Pseudomonas strains revealed high conservation of PQQ biosynthesis and utilization genes, while PqqU showed lower prevalence (47.7%) in the genus. Transcriptional analyses using fluorescent reporters and quantitative reverse transcription PCR demonstrated that PqqU expression remains unchanged in response to PQQ, varying carbon sources, or iron availability, suggesting constitutive regulation. Comparative proteomics between wild-type and ΔpqqABCDEH strains, cultured on glucose or ethanol, uncovered extensive proteomic shifts, underscoring P. aeruginosa’s metabolic adaptability. Additionally, PQQ-dependent metabolic pathways appear to indirectly influence iron homeostasis, most likely through environmental acidification. Together, these results emphasize the critical role of PqqU in PQQ uptake and its broader significance in shaping the metabolic and environmental versatility of Pseudomonas.
SN - 0378-1097
SN - 1574-6968
ER -