3ab1

Crystal Structure of Ferredoxin NADP+ Oxidoreductase

spinqualitylabelsall models 3ab1, resolution 2.39Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ab1 is a 2 chain structure with sequence from Chlorobaculum tepidum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: FAD Activity: Ferredoxin--NADP(+) reductase, with EC number 1.18.1.2 Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed Ferredoxin-NAD(P)(+) oxidoreductase (FNR) catalyzes the reduction of NAD(P)(+) to NAD(P)H with the reduced ferredoxin (Fd) during the final step of the photosynthetic electron transport chain. FNR from the green sulfur bacterium Chlorobaculum tepidum is functionally analogous to plant-type FNR but shares a structural homology to NADPH-dependent thioredoxin reductase (TrxR). Here, we report the crystal structure of C. tepidum FNR to 2.4 A resolution, which reveals a unique structure-function relationship. C. tepidum FNR consists of two functional domains for binding FAD and NAD(P)H that form a homodimer in which the domains are arranged asymmetrically. One NAD(P)H domain is present as the open form, the other with the equivalent NAD(P)H domain as the relatively closed form. We used site-directed mutagenesis on the hinge region connecting the two domains in order to investigate the importance of the flexible hinge. The asymmetry of the NAD(P)H domain and the comparison with TrxR suggested that the hinge motion might be involved in pyridine nucleotide binding and binding of Fd. Surprisingly, the crystal structure revealed an additional C-terminal sub-domain that tethers one protomer and interacts with the other protomer by pi-pi stacking of Phe337 and the isoalloxazine ring of FAD. The position of this stacking Phe337 is almost identical with both of the conserved C-terminal Tyr residues of plant-type FNR and the active site dithiol of TrxR, implying a unique structural basis for enzymatic reaction of C. tepidum FNR. Asymmetric dimeric structure of ferredoxin-NAD(P)+ oxidoreductase from the green sulfur bacterium Chlorobaculum tepidum: implications for binding ferredoxin and NADP+.,Muraki N, Seo D, Shiba T, Sakurai T, Kurisu G J Mol Biol. 2010 Aug 20;401(3):403-14. Epub 2010 Jun 18. PMID:20600130 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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