X-ray Structure and Nuclear Magnetic Resonance Analysis of the Interaction Sites of the Ga-Substituted Cyanobacterial Ferredoxin

Risa Mutoh, Norifumi Muraki, Kanako Shinmura, Hisako Kubota-Kawai, Young Ho Lee, Marc M. Nowaczyk, Matthias Rögner, Toshiharu Hase, Takahisa Ikegami, Genji Kurisu

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

In chloroplasts, ferredoxin (Fd) is reduced by Photosystem I (PSI) and oxidized by Fd-NADP+ reductase (FNR) that is involved in NADP+ reduction. To understand the structural basis for the dynamics and efficiency of the electron transfer reaction via Fd, we complementary used X-ray crystallography and nuclear magnetic resonance (NMR) spectroscopy. In the NMR analysis of the formed electron transfer complex with Fd, the paramagnetic effect of the [2Fe-2S] cluster of Fd prevented us from detecting the NMR signals around the cluster. To solve this problem, the paramagnetic iron-sulfur cluster was replaced with a diamagnetic metal cluster. We determined the crystal structure of the Ga-substituted Fd (GaFd) from Synechocystis sp. PCC6803 at 1.62 Å resolution and verified its functional complementation using affinity chromatography. NMR analysis of the interaction sites on GaFd with PSI (molecular mass of ∼1 MDa) and FNR from Thermosynechococcus elongatus was achieved with high-field NMR spectroscopy. With reference to the interaction sites with FNR of Anabaena sp. PCC 7119 from the published crystal data, the interaction sites of Fd with FNR and PSI in solution can be classified into two types: (1) the core hydrophobic residues in the proximity of the metal center and (2) the hydrophilic residues surrounding the core. The former sites are shared in the Fd:FNR and Fd:PSI complex, while the latter ones are target-specific and not conserved on the residual level.

Original languageEnglish
Pages (from-to)6052-6061
Number of pages10
JournalBiochemistry
Volume54
Issue number39
DOIs
Publication statusPublished - 2015 Oct 6
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry

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