Structural alignment of ferredoxin and flavodoxin based on electrostatic potentials: Implications for their interactions with photosystem I and ferredoxin‐NADP reductase

Ullmann, G. Matthias; Hauswald, Markus; Jensen, Axel; Knapp, Ernst‐Walter

doi:10.1002/(sici)1097-0134(20000215)38:3<301::aid-prot6>3.3.co;2-p

Cited by 7 publications

(7 citation statements)

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“…In addition, structural and functional details of the interaction between specific proteins in PS I and flavodoxin have been described [71][72][73] and a review is also available [74]. The interaction with FNR has also been specifically investigated, mainly in Anabaena PCC 7119 [75][76][77], and models have been proposed for the yet unsolved flavodoxin-FNR complex [78][79]. The stability of the oxidized flavodoxin-FNR complex and the rate of electron transfer between the two proteins seem modulated by a combination of electrostatic and hydrophobic interactions [68,75].…”

Section: Flavodoxin Reactions and Protein Partnersmentioning

confidence: 99%

Flavodoxins: sequence, folding, binding, function and beyond

Sancho

2006

Cell. Mol. Life Sci.

180

234

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Flavodoxins are electron-transfer proteins involved in a variety of photosynthetic and non-photosynthetic reactions in bacteria, whereas, in eukaryotes, a descendant of the flavodoxin gene helps build multidomain proteins. The redox activity of flavodoxin derives from its bound flavin mononucleotide cofactor (FMN), whose intrinsic properties are profoundly modified by the host apoprotein. This review covers the very exciting last decade of flavodoxin research, in which the folding pathway, the structure and stability of the apoprotein, the mechanism of FMN recognition, the interactions that stabilize the functional complex and tailor the redox potentials, and many details of the binding and electron transfer to partner proteins have been revealed. The next decade should witness an even deeper understanding of the flavodoxin molecule and a greater comprehension of its many physiological roles. The fact that flavodoxin is essential for the survival of some human pathogens could make it a drug target on its own.

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Section: Flavodoxin Reactions and Protein Partnersmentioning

confidence: 99%

Flavodoxins: sequence, folding, binding, function and beyond

Sancho

2006

Cell. Mol. Life Sci.

180

234

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“…Using the Hodgkin index as a similarity measure, Ullmann et al . [68] showed that Fd and Fld could be completely overlapped on the basis of their surface electrostatic potentials. The active sites and prosthetic groups of both proteins, rather than their centres of mass, coincided in the alignment [68].…”

Section: Electron Transfer From Reduced Ferredoxin To Ferredoxin‐nadpmentioning

confidence: 99%

Open questions in ferredoxin‐NADP⁺ reductase catalytic mechanism

Carrillo

Ceccarelli

2003

European Journal of Biochemistry

247

290

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Ferredoxin (flavodoxin)-NADP(H) reductases (FNR) are ubiquitous flavoenzymes that deliver NADPH or low potential one-electron donors (ferredoxin, flavodoxin) to redox-based metabolisms in plastids, mitochondria and bacteria. The plant-type reductase is also the basic prototype for one of the major families of flavin-containing electron transferases that display common functional and structural properties. Many aspects of FNR biochemistry have been extensively characterized in recent years using a combination of site-directed mutagenesis, steady-state and transient kinetic experiments, spectroscopy and X-ray crystallography. Despite these considerable advances, various key features in the enzymology of these important reductases remain yet to be explained in molecular terms. This article reviews the current status of these open questions. Measurements of electron transfer rates and binding equilibria indicate that NADP(H) and ferredoxin interactions with FNR result in a reciprocal decrease of affinity, and that this induced-fit step is a mandatory requisite for catalytic turnover. However, the expected conformational movements are not apparent in the reported atomic structures of these flavoenzymes in the free state or in complex with their substrates. The overall reaction catalysed by FNR is freely reversible, but the pathways leading to NADP + or ferredoxin reduction proceed through entirely different kinetic mechanisms. Also, the reductases isolated from various sources undergo inactivating denaturation on exposure to NADPH and other electron donors that reduce the FAD prosthetic group, a phenomenon that might have profound consequences for FNR function in vivo. The mechanisms underlying this reductive inhibition are so far unknown. Finally, we provide here a rationale to interpret FNR evolution in terms of catalytic efficiency. Using the formalism of the Albery-Knowles theory, we identified which parameter(s) have to be modified to make these reductases even more proficient under a variety of conditions, natural or artificial. Flavoenzymes with FNR activity catalyse a number of reactions with potential importance for biotechnological processes, so that modification of their catalytic competence is relevant on both scientific and technical grounds.

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“…Using several charge‐reversal mutants, it has been possible to infer that FNR uses the same site for the interaction with both electron partners, Fd and Fld [27]. Moreover, it has been shown that Fd and Fld could be completely overlapped on the basis of their surface electrostatic potentials [56], but the interaction with Fld has been proposed to involve a larger FNR surface [57]. Although the interaction of FNR with its substrates exhibits co‐operativity [58,59], modifications of the structure that should lead to the observed effects have remained elusive or hard to detect [11,40,60].…”

Section: Discussionmentioning

confidence: 99%

Inhibition of pea ferredoxin–NADP(H) reductase by Zn‐ferrocyanide

Catalano-Dupuy¹,

Rial

Ceccarelli

2004

European Journal of Biochemistry

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Ferredoxin-NADP(H) reductases (FNRs) represent a prototype of enzymes involved in numerous metabolic pathways. We found that pea FNR ferricyanide diaphorase activity was inhibited by Zn 2+ (K i 1.57 lM). Dichlorophenolindophenol diaphorase activity was also inhibited by Zn 2+ (K i 1.80 lM), but the addition of ferrocyanide was required, indicating that the inhibitor is an arrangement of both ions. Escherichia coli FNR was also inhibited by Zn-ferrocyanide, suggesting that inhibition is a consequence of common structural features of these flavoenzymes. The inhibitor behaves in a noncompetitive manner for NADPH and for artificial electron acceptors. Analysis of the oxidation state of the flavin during catalysis in the presence of the inhibitor suggests that the electron-transfer process between NADPH and the flavin is not significantly altered, and that the transfer between the flavin and the second substrate is mainly affected. Zn-ferrocyanide interacts with the reductase, probably increasing the accessibility of the prosthetic group to the solvent. Ferredoxin reduction was also inhibited by Zn-ferrocyanide in a noncompetitive manner, but the observed K i was about nine times higher than those for the diaphorase reactions. The electron transfer to Anabaena flavodoxin was not affected by Zn-ferrocyanide. Binding of the apoflavodoxin to the reductase was sufficient to overcome the inhibition by Zn-ferrocyanide, suggesting that the interaction of FNRs with their proteinaceous electron partners may induce a conformational change in the reductase that alters or completely prevents the inhibitory effect.

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Structural alignment of ferredoxin and flavodoxin based on electrostatic potentials: Implications for their interactions with photosystem I and ferredoxin‐NADP reductase

Cited by 7 publications

References 0 publications

Flavodoxins: sequence, folding, binding, function and beyond

Flavodoxins: sequence, folding, binding, function and beyond

Open questions in ferredoxin‐NADP⁺ reductase catalytic mechanism

Inhibition of pea ferredoxin–NADP(H) reductase by Zn‐ferrocyanide

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Structural alignment of ferredoxin and flavodoxin based on electrostatic potentials: Implications for their interactions with photosystem I and ferredoxin‐NADP reductase

Cited by 7 publications

References 0 publications

Flavodoxins: sequence, folding, binding, function and beyond

Flavodoxins: sequence, folding, binding, function and beyond

Open questions in ferredoxin‐NADP+ reductase catalytic mechanism

Inhibition of pea ferredoxin–NADP(H) reductase by Zn‐ferrocyanide

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Open questions in ferredoxin‐NADP⁺ reductase catalytic mechanism