The University of Southampton
University of Southampton Institutional Repository

Structural and functional characterisation of IdiA/FutA (Tery_3377), an iron binding protein from the ocean diazotroph Trichodesmium erythraeum

Structural and functional characterisation of IdiA/FutA (Tery_3377), an iron binding protein from the ocean diazotroph Trichodesmium erythraeum
Structural and functional characterisation of IdiA/FutA (Tery_3377), an iron binding protein from the ocean diazotroph Trichodesmium erythraeum
Atmospheric nitrogen fixation by photosynthetic cyanobacteria (diazotrophs) strongly influences oceanic primary production and in turn affects global biogeochemical cycles. Species of the genus Trichodesmium are major contributors to marine diazotrophy, accounting for a significant proportion of the fixed nitrogen in tropical and subtropical oceans. However, Trichodesmium spp. are metabolically constrained by the availability of iron, an essential element for both the photosynthetic apparatus and the nitrogenase enzyme. Survival strategies in low-iron environments are typically poorly characterized at the molecular level, as these bacteria are recalcitrant to genetic manipulation. Here, we studied a homolog of the iron deficiency-induced A (IdiA)/ferric uptake transporter A (FutA) protein, Tery_3377, which has been used as an in situ iron-stress biomarker. IdiA/FutA has an ambiguous function in cyanobacteria, with its homologs hypothesized to be involved in distinct processes depending on their cellular localization. Using signal sequence fusions to GFP and heterologous expression in the model cyanobacterium Synechocystis sp. PCC 6803 we show that Tery_3377 is targeted to the periplasm by the twin-arginine translocase and can complement the deletion of the native Synechocystis ferric-iron ABC transporter periplasmic binding protein (FutA2). EPR spectroscopy revealed that purified recombinant Tery_3377 has specificity for iron in the Fe3+ state, and an X-ray crystallography determined structure uncovered a functional iron substrate-binding domain, with Fe3+ penta-coordinated by protein and buffer ligands. Our results support assignment of Tery_3377 as a functional FutA subunit of an Fe3+ ABC-transporter, but do not rule out that it also has dual IdiA function.
1083-351X
Polyviou, Despo
57dea764-2c54-44bb-a7ac-382ba19418cb
Machelett, Moritz
c9aa7658-2a08-48d6-9ce1-8c3b6d00a58c
Hitchcock, Andrew
aeca86f3-e8cf-47d1-9338-e82630fb868e
Bayley, Alison J.
aa666749-767e-4b27-a83c-1907e5def3f9
MacMillan, Fraser
7c37a816-8dba-4b1d-b003-6d1b50024191
Moore, C. Mark
7045f61a-cf1f-4e60-819b-3cadc9195bf2
Bibby, Thomas
e04ea079-dd90-4ead-9840-00882de27ebd
Tews, Ivo
9117fc5e-d01c-4f8d-a734-5b14d3eee8dd
Polyviou, Despo
57dea764-2c54-44bb-a7ac-382ba19418cb
Machelett, Moritz
c9aa7658-2a08-48d6-9ce1-8c3b6d00a58c
Hitchcock, Andrew
aeca86f3-e8cf-47d1-9338-e82630fb868e
Bayley, Alison J.
aa666749-767e-4b27-a83c-1907e5def3f9
MacMillan, Fraser
7c37a816-8dba-4b1d-b003-6d1b50024191
Moore, C. Mark
7045f61a-cf1f-4e60-819b-3cadc9195bf2
Bibby, Thomas
e04ea079-dd90-4ead-9840-00882de27ebd
Tews, Ivo
9117fc5e-d01c-4f8d-a734-5b14d3eee8dd

Polyviou, Despo, Machelett, Moritz, Hitchcock, Andrew, Bayley, Alison J., MacMillan, Fraser, Moore, C. Mark, Bibby, Thomas and Tews, Ivo (2018) Structural and functional characterisation of IdiA/FutA (Tery_3377), an iron binding protein from the ocean diazotroph Trichodesmium erythraeum. The Journal of Biological Chemistry. (doi:10.1074/jbc.RA118.001929).

Record type: Article

Abstract

Atmospheric nitrogen fixation by photosynthetic cyanobacteria (diazotrophs) strongly influences oceanic primary production and in turn affects global biogeochemical cycles. Species of the genus Trichodesmium are major contributors to marine diazotrophy, accounting for a significant proportion of the fixed nitrogen in tropical and subtropical oceans. However, Trichodesmium spp. are metabolically constrained by the availability of iron, an essential element for both the photosynthetic apparatus and the nitrogenase enzyme. Survival strategies in low-iron environments are typically poorly characterized at the molecular level, as these bacteria are recalcitrant to genetic manipulation. Here, we studied a homolog of the iron deficiency-induced A (IdiA)/ferric uptake transporter A (FutA) protein, Tery_3377, which has been used as an in situ iron-stress biomarker. IdiA/FutA has an ambiguous function in cyanobacteria, with its homologs hypothesized to be involved in distinct processes depending on their cellular localization. Using signal sequence fusions to GFP and heterologous expression in the model cyanobacterium Synechocystis sp. PCC 6803 we show that Tery_3377 is targeted to the periplasm by the twin-arginine translocase and can complement the deletion of the native Synechocystis ferric-iron ABC transporter periplasmic binding protein (FutA2). EPR spectroscopy revealed that purified recombinant Tery_3377 has specificity for iron in the Fe3+ state, and an X-ray crystallography determined structure uncovered a functional iron substrate-binding domain, with Fe3+ penta-coordinated by protein and buffer ligands. Our results support assignment of Tery_3377 as a functional FutA subunit of an Fe3+ ABC-transporter, but do not rule out that it also has dual IdiA function.

Text
JBC-2018-001929 - Accepted Manuscript
Restricted to Repository staff only until 14 September 2019.
Available under License Other.
Request a copy

More information

Accepted/In Press date: 14 September 2018
e-pub ahead of print date: 14 September 2018

Identifiers

Local EPrints ID: 425434
URI: https://eprints.soton.ac.uk/id/eprint/425434
ISSN: 1083-351X
PURE UUID: 74a04b6a-ccf2-4d02-9883-85decb96c2a6
ORCID for Ivo Tews: ORCID iD orcid.org/0000-0002-4704-1139

Catalogue record

Date deposited: 19 Oct 2018 16:30
Last modified: 15 Aug 2019 00:39

Export record

Altmetrics

Contributors

Author: Despo Polyviou
Author: Moritz Machelett
Author: Andrew Hitchcock
Author: Alison J. Bayley
Author: Fraser MacMillan
Author: C. Mark Moore
Author: Thomas Bibby
Author: Ivo Tews ORCID iD

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×