Interaction of ferredoxin with ferredoxin:NADP reductase: Effects of chemical modification of ferredoxin

Vieira, Barbara J.; Davis, Danny J.

doi:10.1016/0003-9861(86)90542-4

Cited by 17 publications

(7 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Titrations of unmodified, native ferredoxin (not shown) gave Em = -423 f 5 mV (n = l.O), in good agreement with literature values [ 17,24,25]. These observations, coupled with the previous observation that carboxyl group modification affects neither the visible absorbance spectrum of ferredoxin nor the protein's ability to be photo-reduced by chloroplast photosystem I [12,22], suggest that the modification has no effect on the redox properties or im-. mediate environment of ferredoxin's [2Fe-2S] cluster.…”

Section: Resultssupporting

confidence: 88%

“…The latter observation contrasts with that observed for other ferredoxin-dependent plant enzymes, such as glutamate synthase (where modification of ferredoxin carboxyl groups increased K,,, 42-fold and decreased V,,,,, 5-fold [ 1 I]), nitrite reductase (where modification decreased V,,, 5-fold [ 111) and NADP+ reductase (where modification decreased activity 5-fold [12,22]). This result is similar, in one respect, to that obtained with spinach nitrite reductase (an enzyme that is closely related to sulfite reductase [4,5]) in that the K,,, for ferredoxin was not affected by carboxyl group modification [ 111.…”

Section: Discussionmentioning

confidence: 86%

See 1 more Smart Citation

The interaction of ferredoxin‐linked sulfite reductase with ferredoxin

et al. 1987

Self Cite

View full text Add to dashboard Cite

Spinach sulfite reductase has been shown to co-migrate during gel filtration chromatography at low ionic strength with spinach ferredoxin. No co-migration was observed at high ionic strength. These results indicate that the two proteins form a high-affinity, electrostatically stabilized complex, as had previously been demonstrated for three other ferredoxin-dependent, plant enzymes. Modification of 3-4 ferredoxin carboxyl groups had little detectable effect on the ferredoxin-sulfite reductase interaction.Sulfite-reductase; Ferredoxin; (Spinach)

show abstract

Section: Resultssupporting

confidence: 88%

Section: Discussionmentioning

confidence: 86%

The interaction of ferredoxin‐linked sulfite reductase with ferredoxin

et al. 1987

Self Cite

View full text Add to dashboard Cite

show abstract

“…3, 34 Chemical modification studies have been used to explore the effects of eliminating these negative charges on the ability of Fd to interact productively with target enzymes, and the results of these studies support the hypothesis that Fd does indeed contribute negative charges to the stabilization of these complexes. 35 Additionally, site-directed mutagenesis has also provided evidence that negatively charged Fd amino acids of Anabaena sp. PCC 7120 36 and spinach 33 are crucial for electron transfer from Fd to ferredoxin:NADP + reductase (FNR) and involved in the formation of an electrostatic complex with positively charged amino acids of FNR.…”

Section: Discussionmentioning

confidence: 99%

Identification of the Ferredoxin-Binding Site of a Ferredoxin-Dependent Cyanobacterial Nitrate Reductase

et al. 2017

View full text Add to dashboard Cite

An in silico model for the 1:1 ferredoxin (Fd)/nitrate reductase (NR) complex, using the known structure of Synechocystis sp. PCC 6803 Fd and the in silico model of Synechococcus sp. PCC 7942 NR, is used to map the interaction sites that define the interface between Fd and NR. To test the electrostatic interactions predicted by the model complex, five positively charged NR amino acids (Arg43, Arg46, Arg197, Lys201, and Lys614) and a negatively charged amino acid (Glu219) were altered using site-directed mutagenesis and characterized by activity measurements, metal analysis, and electron paramagnetic resonance (EPR) studies. All of the charge replacement variants retained wild-type levels of activity with reduced methyl viologen (MV), but a significant decrease in activity was observed for the R43Q, R46Q, K201Q, and K614Q variants when reduced Fd served as the electron donor. EPR analysis as well as the Fe and Mo analyses showed that loss of activity observed with these variants was not the consequence of perturbation of the Mo center or [4Fe-4S] cluster. Therefore, the loss of the Fd-linked specific activity observed with these variants can be explained only by invoking a role for Arg43, Arg46, Lys201, and Lys614 in Fd binding. The R43Q, R46Q, K201Q, and K614Q NR variants also showed a decreased binding affinity for Fd, compared to that of wild-type NR, supporting a key role of these four positively charged residues in the productive binding of Fd.

show abstract

“…Carboxyl modification of Fd was carried out according to Vieira and Davis (1986). Fd at lmgml -~ in the presence of 0.5M glycine methyl ester (GME) was modified with N -(dimethylaminopropyl) -N' -ethylcarbodiimide (EDC) at a final concentration of 20 mM added from a stock solution prepared immediately prior to use.…”

Section: Methodsmentioning

confidence: 99%

“…We employed the modification of Fd to explore further the role of FNR in cyclic activity by altering the interaction of Fd with FNR through the modification of carboxyl residues by EDC. Such treatment prevents Fd from donating electrons to F N R although it can still pass electrons to cytochrome c (Vieira and Davis 1986). Figure 6 shows the timecourse of the effect of E D C on the ability of Fd to interact with FNR, cytochrome c and to participate in the cyclic assay.…”

Section: When the Light Was Switched Off A463 Increasedmentioning

confidence: 99%

Photosystem I cyclic electron transport: Measurement of ferredoxin-plastoquinone reductase activity

1992

View full text Add to dashboard Cite

Absorbance changes of ferredoxin measured at 463 nm in isolated thylakoids were shown to arise from the activity of the enzyme ferredoxin-plastoquinone reductase (FQR) in cyclic electron transport. Under anaerobic conditions in the presence of DCMU and an appropriate concentration of reduced ferredoxin, a light-induced absorbance decrease due to further reduction of Fd was assigned to the oxidation of the other components in the cyclic pathway, primarily plastoquinone. When the light was turned off, Fd was reoxidised and this gave a direct quantitative measurement of the rate of cyclic electron transport due to the activity of FQR. This activity was sensitive to the classical inhibitor of cyclic electron transport, antimycin, and also to J820 and DBMIB. Antimycin had no effect on Fd reduction although this was inhibited by stigmatellin. This provides further evidence that there is a quinone reduction site outside the cytochrome bf complex. The effect of inhibitors of ferredoxin-NADP(+) reductase and experiments involving the modification of ferredoxin suggest that there may be some role for the reductase as a component of FQR. Contrary to expectations, NADPH2 inhibited FQR activity; ATP and ADP had no effect.

show abstract

Interaction of ferredoxin with ferredoxin:NADP reductase: Effects of chemical modification of ferredoxin

Cited by 17 publications

References 25 publications

The interaction of ferredoxin‐linked sulfite reductase with ferredoxin

The interaction of ferredoxin‐linked sulfite reductase with ferredoxin

Identification of the Ferredoxin-Binding Site of a Ferredoxin-Dependent Cyanobacterial Nitrate Reductase

Photosystem I cyclic electron transport: Measurement of ferredoxin-plastoquinone reductase activity

Contact Info

Product

Resources

About