Algal ferredoxin

Fig. 16. Absorbance changes measured at 480 nm and associated with ferredoxin reduction induced at 660-nm by 1-r s dye laser flashes. (A) In the absence and presence of spinach ferredoxin baseline for each trace is shifted for clarity (B) plot of rate constant vs. concentration of ferredoxins from spinach and the green alga Monoraphidium braunni. Figure source Herv s, Navarro and Toltin (1992) A laser flash spectroscopy study of the kinetics of electron transfer from spinach photosystem I to spinach and algal ferredoxins. Photochem Photobiol 56 321.

R.E. Anderson, et al.. Nature of iron sulfur cluster in a deuterated algal ferredoxin, Biochim. Biophys. Acta 1975, 408(3), 306-318. 

The last step in the photosynthetic algal H2 production process occurs with the sequential transfer of two negative charges from reduced ferredoxin to a soluble [FeFe] hydrogenase,98,216 which is almost isoenergetic (A/hi = 0.020)11 with ferre... 

The oxidized P700 is reduced by the copper protein, plastocyanin, present in the lumenal space ofthe thylakoid. Reflecting the overall reaction it supports, the PS-1 reaction center is sometimes called plastocyanin ferredoxin oxidoreductase. Note that in cyanobacteria the corresponding electron donor is cytochrome c552 rather than plastocyanin and some algal species when in a copper-deficient medium synthesize a c-type cytochrome as a replacement for plastocyanin. The complete electron-transport chain ofphotosystem 1 is shown in Fig. 2. The approximate redox potentials and halftimes for forward electron transfers at ambient temperature are also indicated. Perhaps to assure wasteful back reactions are mini-... 

Figure 1. Proton magnetic resoruince spectra at 220 MHz (Varian HR 220 spectrometer in the fast fourier transform pulse mode) of fuUy deuterated algal ferre-doxin. About 26 slowly exchangeable protons (Spectrum I) are observable after back exchange in HgO buffer at pH 9. After 3 hrs at 60°C in H,0 buffer, pH 7.2, 11 of these protons have completely out exchanged and 15 have been quite resistant to exchange (Spectrum 11). These data indicate that this ferredoxin molecule contains two segments of helix (or pleated-sheet) secondary structure.

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