Azotobacter vinelandii scaffold protein NifU transfers iron to NifQ as part of the iron-molybdenum cofactor biosynthesis pathway for nitrogenase
The Azotobacter vinelandii molybdenum nitrogenase obtains molybdenum from NifQ, a monomeric iron-sulfur molybdoprotein. This protein requires an existing [Fe-S] cluster to form a [Mo-Fe<sub>3</sub>-S<sub>4</sub>] group, which acts as a specific molybdenum donor during nitrogenase FeMo-co biosynthesis. Here, we show biochemical evidence supporting the role of NifU as the [Fe-S] cluster donor. Protein-protein interaction studies involving apo-NifQ and as-isolated NifU demonstrated their interaction, which was only effective when NifQ lacked its [Fe-S] cluster. Incubation of apo-NifQ with [Fe<sub>4</sub>-S<sub>4</sub>]-loaded NifU increased the iron content of the former, contingent on both proteins being able to interact with one another. As a result of this interaction, a [Fe<sub>4</sub>-S<sub>4</sub>] cluster was transferred from NifU to NifQ. In A. vinelandii, NifQ was preferentially metalated by NifU rather than by the [Fe-S] cluster scaffold protein IscU. These results indicate the necessity of co-expressing NifU and NifQ to efficiently provide molybdenum for FeMo-co biosynthesis when engineering nitrogenase in plants.
Authors
- Carlos Echávarri‐Erasun (ORCID: https://orcid.org/0000-0001-8363-5199)
- Yisong Guo (ORCID: https://orcid.org/0000-0002-4132-3565)
- Jin Xiong (ORCID: https://orcid.org/0000-0001-7443-0554)
- Emma Barahona (ORCID: https://orcid.org/0000-0002-9842-2185)
- Manuel González‐Guerrero (ORCID: https://orcid.org/0000-0001-7334-5286)
- Elena Rosa‐Núñez (ORCID: https://orcid.org/0009-0007-5114-9429)
- Luis M. Rubio (ORCID: https://orcid.org/0000-0003-1596-2475)
- Emilio Jiménez‐Vicente (ORCID: https://orcid.org/0000-0002-3347-3096)
- Xi Jiang (ORCID: https://orcid.org/0000-0002-1819-9041)
- Juan Andrés Collantes-García
Institutions
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (ES)
- Centre for Plant Biotechnology and Genomics (ES)
- Carnegie Mellon University (US)
- Virginia Tech (US)
- Universidad Politécnica de Madrid (ES)
Publication Details
- Journal
- Journal of Biological Chemistry
- Published
- 2024-10-21
- DOI
- https://doi.org/10.1016/j.jbc.2024.107900
- Citations
- 2
- Primary Topic
- Metalloenzymes and iron-sulfur proteins
- Type
- article
- Field-Weighted Citation Impact
- 0.20
Funders
- Foundation for the National Institutes of Health
- Bill and Melinda Gates Foundation
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria
- Ministerio de Ciencia e Innovación
- National Institutes of Health
- European Regional Development Fund
- Agencia Estatal de Investigación