Arabidopsis FNRL protein is an NADPH-dependent chloroplast oxidoreductase resembling bacterial ferredoxin-NADP+ reductases

Koskela, M.M. ; Dahlström, K.M. ; Goñi, G. ; Lehtimäki, N. ; Nurmi, M. ; Velazquez-Campoy, A. (Universidad de Zaragoza) ; Hanke, G. ; Bölter, B. ; Salminen, T.A. ; Medina, M. (Universidad de Zaragoza) ; Mulo, P.

Resumen: Plastidic ferredoxin-NADP+ oxidoreductases (FNRs; EC:1.18.1.2) together with bacterial type FNRs (FPRs) form the plant-type FNR family. Members of this group contain a two-domain scaffold that forms the basis of an extended superfamily of flavin adenine dinucleotide (FAD) dependent oxidoreductases. In this study, we show that the Arabidopsis thaliana At1g15140 [Ferredoxin-NADP+ oxidoreductase-like (FNRL)] is an FAD-containing NADPH dependent oxidoreductase present in the chloroplast stroma. Determination of the kinetic parameters using the DCPIP NADPH-dependent diaphorase assay revealed that the reaction catalysed by a recombinant FNRL protein followed a saturation Michaelis–Menten profile on the NADPH concentration with kcat = 3.2 ± 0.2 s-1, Km NADPH = 1.6 ± 0.3 µM and kcat/Km NADPH = 2.0 ± 0.4 µM-1 s-1. Biochemical assays suggested that FNRL is not likely to interact with Arabidopsis ferredoxin 1, which is supported by the sequence analysis implying that the known Fd-binding residues in plastidic FNRs differ from those of FNRL. In addition, based on structural modelling FNRL has an FAD-binding N-terminal domain built from a six-stranded ß-sheet and one a-helix, and a C-terminal NADP+-binding a/ß domain with a five-stranded ß-sheet with a pair of a-helices on each side. The FAD-binding site is highly hydrophobic and predicted to bind FAD in a bent conformation typically seen in bacterial FPRs.

Idioma: Inglés

DOI: 10.1111/ppl.12621

Año: 2018

Publicado en: PHYSIOLOGIA PLANTARUM 162, 2 (2018), 177-190
ISSN: 0031-9317

Factor impacto JCR: 3.0 (2018)

Categ. JCR: PLANT SCIENCES rank: 48 / 226 = 0.212 (2018) - Q1 - T1

Factor impacto SCIMAGO: 1.23 - Cell Biology (Q1) - Genetics (Q1) - Plant Science (Q1) - Physiology (Q1) - Medicine (miscellaneous) (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/B18
Financiación: info:eu-repo/grantAgreement/ES/MINECO/BIO2016-75183-P

Tipo y forma: Article (PostPrint)

Área (Departamento): Área Bioquímica y Biolog.Mole. (Dpto. Bioq.Biolog.Mol. Celular)