Identification of the ferredoxin interaction sites on ferredoxin-dependent glutamate synthase from Synechocystis sp. PCC 6803

Masakazu Hirasawa, Jacaranda Solis, Nanditha Vaidyanathan, Anurag P. Srivastava, R. Max Wynn, Roger B. Sutton, David B. Knaff

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Based on in silico docking methods, five amino acids in glutamate synthase (Gln-467, His-1144, Asn-1147, Arg-1162, and Trp-676) likely constitute key binding residues in the interface of a glutamate synthase:ferredoxin complex. Although all interfacial mutants studied showed the ability to form a complex under low ionic strength, these docking mutations showed significantly less ferredoxin-dependent activities, while still retaining enzymatic activity. Furthermore, isothermal titration calorimetry showed a possible 1:2 molar ratio between the wild-type glutamate synthase and ferredoxin. However, each of our interfacial mutants showed only a 1:1 complex with ferredoxin, suggesting that the mutations directly affect the glutamate synthase:ferredoxin heterodimer interface.

Original languageEnglish (US)
Pages (from-to)317-328
Number of pages12
JournalPhotosynthesis Research
Volume134
Issue number3
DOIs
StatePublished - Dec 1 2017

Keywords

  • Electrostatic interactions
  • Ferredoxin
  • Flavin mononucleotide (FMN)
  • Glutamate synthase
  • In silico docking
  • Iron–sulfur-binding sites
  • Isothermal titration calorimetry
  • Site-directed mutagenesis
  • Spectral perturbation

ASJC Scopus subject areas

  • Biochemistry
  • Plant Science
  • Cell Biology

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