Structure and reactivity of a siderophore-interacting protein from the marine bacterium Shewanella reveals unanticipated functional versatility

Autor: Masaki J. Fujita, Bruno M. Fonseca, Inês B. Trindade, Pedro M. Matias, José Madeira da Silva, Ricardo O. Louro, Teresa Catarino, Elin Moe
Přispěvatelé: Instituto de Tecnologia Química e Biológica António Xavier (ITQB), Molecular, Structural and Cellular Microbiology (MOSTMICRO), DQ - Departamento de Química, Bioresources 4 Sustainability (GREEN-IT)
Rok vydání: 2019
Předmět:
Zdroj: Journal of Biological Chemistry
Repositório Científico de Acesso Aberto de Portugal
Repositório Científico de Acesso Aberto de Portugal (RCAAP)
instacron:RCAAP
ISSN: 0021-9258
DOI: 10.1074/jbc.ra118.005041
Popis: This work was supported by the European Union’s Horizon 2020 research and innovation program under Grant 810856, National Funds Grant ERA-MBT/ 0003/2014, Ph.D. fellowship PD/BD/135187/2017 (to I. B. T.), and postdoctoral fellowships SFRH/BPD/94050/2013 and SFRH/BPD/93164/2013 (to E. M. and B. F. M.), through the FCT-Fundação para a Ciência e Tecnologia. The authors declare that they have no conflicts of interest with the contents of this article. Acknowledgments—We thank Isabel Pacheco for help in the purification of SfSIP and Dr. Américo Duarte for providing ferredoxin. We also thank all members of the Inorganic Biochemistry and NMR Laboratory for discussions and comments and feedback regarding the preparation of the manuscript. The NMR experiments were performed at CERMAX (Centro de Ressonância Magnetica António Xavier) and was financially supported by Project LISBOA-01-0145-FEDER-007660 (Microbiologia Molecular, Estrutural e Celular) funded by FEDER funds through COMPETE2020-Programa Opera-cional Competitividade e Internacionalização (POCI), the European Community’s Seventh Framework Program (FP7/2007–2013)) under Grant Agreement 283570 (BioStruct-X). Beamtime at I04 at the Diamond Light Source and assistance from the beamline staff during the synchrotron data collections are gratefully acknowledged. Siderophores make iron accessible under iron-limited conditions and play a crucial role in the survival of microorganisms. Because of their remarkable metal-scavenging properties and ease in crossing cellular envelopes, siderophores hold great potential in biotechnological applications, raising the need for a deeper knowledge of the molecular mechanisms underpinning the siderophore pathway. Here, we report the structural and functional characterization of a siderophore-interacting protein from the marine bacterium Shewanella frigidimarina NCIBM400 (SfSIP). SfSIP is a flavin-containing ferric-siderophore reductase with FAD- and NAD(P)H-binding domains that have high homology with other characterized SIPs. However, we found here that it mechanistically departs from what has been described for this family of proteins. Unlike other FAD-containing SIPs, SfSIP did not discriminate between NADH and NADPH. Furthermore, SfSIP required the presence of the Fe 2+ -scavenger, ferrozine, to use NAD(P)H to drive the reduction of Shewanella-produced hydroxamate ferric-siderophores. Additionally, this is the first SIP reported that also uses a ferredoxin as electron donor, and in contrast to NAD(P)H, its utilization did not require the mediation of ferrozine, and electron transfer occurred at fast rates. Finally, FAD oxidation was thermodynamically coupled to deprotonation at physiological pH values, enhancing the solubility of ferrous iron. On the basis of these results and the location of the SfSIP gene downstream of a sequence for putative binding of aerobic respiration control protein A (ArcA), we propose that SfSIP contributes an additional layer of regulation that maintains cellular iron homeostasis according to environmental cues of oxygen availability and cellular iron demand. publishersversion published
Databáze: OpenAIRE
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