Molecular organizations and function of iron-stress-induced-A protein family in Anabaena sp. PCC 7120

Ryo Nagao, Makio Yokono, Yoshifumi Ueno, Takehiro Suzuki, Koji Kato, Ka Ho Kato, Naoki Tsuboshita, Tian Yi Jiang, Naoshi Dohmae, Jian Ren Shen, Shigeki Ehira, Seiji Akimoto

Research output: Contribution to journalArticlepeer-review

Abstract

Iron-stress-induced-A proteins (IsiAs) are expressed in cyanobacteria under iron-deficient conditions, and surround photosystem I (PSI) trimer with a ring formation. A cyanobacterium Anabaena sp. PCC 7120 has four isiA genes; however, it is unknown how the IsiAs are associated with PSI. Here we report on molecular organizations and function of the IsiAs in this cyanobacterium. A deletion mutant of the isiA1 gene was constructed, and the four types of thylakoids were prepared from the wild-type (WT) and ΔisiA1 cells under iron-replete (+Fe) and iron-deficient (−Fe) conditions. Immunoblotting analysis exhibits a clear expression of the IsiA1 in the WT−Fe. The PSI-IsiA1 supercomplex is found in the WT−Fe, and excitation-energy transfer from IsiA1 to PSI is verified by time-resolved fluorescence analyses. Instead of the IsiA1, both IsiA2 and IsiA3 are bound to PSI monomer in the ΔisiA1−Fe. These findings provide insights into multiple-expression system of the IsiA family in this cyanobacterium.

Original languageEnglish
Article number148327
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume1862
Issue number1
DOIs
Publication statusPublished - Jan 1 2021

Keywords

  • Anabaena sp. PCC 7120
  • Iron deficient
  • IsiA
  • Time-resolved fluorescence

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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