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

Devendra Chauhan, I. Mihaela Folea, Craig C. Jolley, Roman Kour̂il, Carolyn E. Lubner, Su Lin, Dorota Kolber, Felisa Wolfe-Simon, John H. Golbeck, Egbert J. Boekema, Petra Fromme

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)686-692
Number of pages7
Issue number5
StatePublished - Feb 8 2011

All Science Journal Classification (ASJC) codes

  • Biochemistry


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