ja7b04893_si_001.pdf (893.36 kB)
The In Vivo Potential-Regulated Protective Protein of Nitrogenase in Azotobacter vinelandii Supports Aerobic Bioelectrochemical Dinitrogen Reduction In Vitro
journal contribution
posted on 2017-06-08, 00:00 authored by Ross D. Milton, Rong Cai, Selmihan Sahin, Sofiene Abdellaoui, Bassam Alkotaini, Dónal Leech, Shelley D. MinteerNitrogenase,
the only enzyme known to be able to reduce dinitrogen
(N2) to ammonia (NH3), is irreversibly damaged
upon exposure to molecular oxygen (O2). Several microbes,
however, are able to grow aerobically and diazotrophically (fixing
N2 to grow) while containing functional nitrogenase. The
obligate aerobic diazotroph, Azotobacter vinelandii, employs a multitude of protective mechanisms to preserve nitrogenase
activity, including a “conformational switch” protein
(FeSII, or “Shethna”) that reversibly locks nitrogenase
into a multicomponent protective complex upon exposure to low concentrations
of O2. We demonstrate in vitro that nitrogenase can be
oxidatively damaged under anoxic conditions and that the aforementioned
conformational switch can protect nitrogenase from such damage, confirming
that the conformational change in the protecting protein can be achieved
solely by regulating the potential of its [2Fe-2S] cluster. We further
demonstrate that this protective complex preserves nitrogenase activity
upon exposure to air. Finally, this protective FeSII protein was incorporated
into an O2-tolerant bioelectrosynthetic cell whereby NH3 was produced using air as a substrate, marking a significant
step forward in overcoming the crippling limitation of nitrogenase’s
sensitivity toward O2.
History
Usage metrics
Categories
- Biophysics
- Biochemistry
- Physical Sciences not elsewhere classified
- Microbiology
- Cell Biology
- Molecular Biology
- Environmental Sciences not elsewhere classified
- Astronomical and Space Sciences not elsewhere classified
- Immunology
- Biological Sciences not elsewhere classified
- Developmental Biology
- Computational Biology
Keywords
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC