A novel photosynthetic strategy for adaptation to low-iron aquatic environments

Biochemistry
By: , and 

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Abstract

Iron (Fe) availability is a major limiting factor for primary production in aquatic environments. Cyanobacteria respond to Fe deficiency by derepressing the isiAB operon, which encodes the antenna protein IsiA and flavodoxin. At nanomolar Fe concentrations, a PSI−IsiA supercomplex forms, comprising a PSI trimer encircled by two complete IsiA rings. This PSI−IsiA supercomplex is the largest photosynthetic membrane protein complex yet isolated. This study presents a detailed characterization of this complex using transmission electron microscopy and ultrafast fluorescence spectroscopy. Excitation trapping and electron transfer are highly efficient, allowing cyanobacteria to avoid oxidative stress. This mechanism may be a major factor used by cyanobacteria to successfully adapt to modern low-Fe environments.

Publication type Article
Publication Subtype Journal Article
Title A novel photosynthetic strategy for adaptation to low-iron aquatic environments
Series title Biochemistry
DOI 10.1021/bi1009425
Volume 50
Issue 5
Year Published 2011
Language English
Publisher American Chemical Society
Description 7 p.
First page 686
Last page 692
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