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Biochim Biophys Acta. 2016 Nov;1857(11):1766-1776. doi: 10.1016/j.bbabio.2016.08.003. Epub 2016 Aug 12.

The two Dps proteins, NpDps2 and NpDps5, are involved in light-induced oxidative stress tolerance in the N2-fixing cyanobacterium Nostoc punctiforme.

Author information

1
Department of Chemistry - Ångström Laboratory, Uppsala University, SE - 751 20 Uppsala, Sweden.
2
Department of Chemistry - Ångström Laboratory, Uppsala University, SE - 751 20 Uppsala, Sweden; Copenhagen Plant Science Centre (CPSC), Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.
3
Department of Chemistry - Ångström Laboratory, Uppsala University, SE - 751 20 Uppsala, Sweden; Department of Molecular Biology, 6K och 6L Sjukhusområdet, Umeå University, 90187, Umeå, Sweden.
4
Department of Chemistry - Ångström Laboratory, Uppsala University, SE - 751 20 Uppsala, Sweden; Department of Ecology, Environment and Plant Sciences, SciLifeLab, Stockholm University, Box 1031, 171 21 Solna, Sweden.
5
Department of Chemistry - Ångström Laboratory, Uppsala University, SE - 751 20 Uppsala, Sweden. Electronic address: Ann.Magnuson@kemi.uu.se.
6
Department of Chemistry - Ångström Laboratory, Uppsala University, SE - 751 20 Uppsala, Sweden. Electronic address: Karin.Stensjo@kemi.uu.se.

Abstract

Cyanobacteria are photosynthetic prokaryotes that are considered biotechnologically prominent organisms for production of high-value compounds. Cyanobacteria are subject to high-light intensities, which is a challenge that needs to be addressed in design of efficient bio-engineered photosynthetic organisms. Dps proteins are members of the ferritin superfamily and are omnipresent in prokaryotes. They play a major role in oxidative stress protection and iron homeostasis. The filamentous, heterocyst-forming Nostoc punctiforme, has five Dps proteins. In this study we elucidated the role of these Dps proteins in acclimation to high light intensity, the gene loci organization and the transcriptional regulation of all five dps genes in N. punctiforme was revealed, and dps-deletion mutant strains were used in physiological characterization. Two mutants defective in Dps2 and Dps5 activity displayed a reduced fitness under increased illumination, as well as a differential Photosystem (PS) stoichiometry, with an elevated Photosystem II to Photosystem I ratio in the dps5 deletion strain. This work establishes a Dps-mediated link between light tolerance, H2O2 detoxification, and iron homeostasis, and provides further evidence on the non-redundant role of multiple Dps proteins in this multicellular cyanobacterium.

KEYWORDS:

ROS; adaptation; cyanobacteria; ferritin; light-stress; photosystem

PMID:
27528559
DOI:
10.1016/j.bbabio.2016.08.003
[Indexed for MEDLINE]
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