NADP(H) allosterically regulates the interaction between ferredoxin and ferredoxin‐NADP+ reductase

• Published in: FEBS open bio Vol. 9; no. 12; pp. 2126 - 2136
• Main Authors: Kimata‐Ariga, Yoko, Chikuma, Yutaro, Saitoh, Takashi, Miyata, Masayuki, Yanagihara, Yuetsu, Yamane, Kazukiyo, Hase, Toshiharu
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.12.2019; John Wiley and Sons Inc; Wiley
• Subjects: Affinity; Allosteric properties; allosteric regulation; Amino Acid Sequence - genetics; Binding sites; Chloroplasts; Chromatography; Cytochrome; Electron transfer; Electron Transport - genetics; Electron Transport - physiology; Enzymes; Experiments; Ferredoxin; Ferredoxin-NADP Reductase - genetics; Ferredoxin-NADP Reductase - metabolism; Ferredoxin-NADP Reductase - physiology; Ferredoxins - metabolism; ferredoxin‐NADP+ reductase; Kinetics; Models, Molecular; Mutagenesis; Mutation; NADP; NADP - metabolism; negative cooperativity; Oxidation-Reduction; Photosynthesis - genetics; Physiology; Protein Conformation; Proteins; Reductase; Spectrum analysis; Zea mays - genetics; Zea mays - metabolism; United States > US; Japan; negative cooperativity; ferredoxin; allosteric regulation; ferredoxin-NADP+ reductase
• ISSN: 2211-5463; 2211-5463
• DOI: 10.1002/2211-5463.12752

Ferredoxin‐NADP+ reductase (FNR) in plants receives electrons from ferredoxin (Fd) at the end of the photosynthetic electron transfer chain and converts NADP+ to NADPH. The interaction between Fd and FNR in plants was previously shown to be attenuated by NADP(H). Here, we investigated the molecular mechanism of this phenomenon using maize FNR and Fd, as the three‐dimensional structure of this complex is available. NADPH, NADP+, and 2′5′‐ADP differentially affected the interaction, as revealed through kinetic and physical binding analyses. Site‐directed mutations of FNR which change the affinity for NADPH altered the affinity for Fd in the opposite direction to that for NADPH. We propose that the binding of NADP(H) causes a conformational change of FNR which is transferred to the Fd‐binding region through different domains of FNR, resulting in allosteric changes in the affinity for Fd. The interaction between ferredoxin (Fd) and Fd‐NADP+ reductase (FNR) in plants is attenuated by NADP(H). Site‐directed mutations of FNR which change the affinity for NADPH altered the affinity for Fd in the opposite direction. We propose that the binding of NADP(H) leads to conformational changes of FNR, resulting in allosteric changes in the affinity for Fd.