Evolution of Chlamydomonas reinhardtii ferredoxins and their interactions with [FeFe]-hydrogenases

Abstract

Ferredoxins are soluble iron sulphur proteins which function as electron donors in a number of metabolic pathways in a broad range of organisms. In photosynthetic organisms, PETF, or ferredoxin 1 (FDX1), is the most studied ferredoxin due to its essential role in photosynthesis, where it transfers electrons from photosystem I to ferredoxin-NADP oxidoreductase. However, PETF can also transfer electrons to a large number of other proteins. One important PETF electron acceptor found in green microalgae is the biologically and biotechnologically important [FeFe]-hydrogenase HYDA, which catalyses the production of molecular hydrogen (H) from protons and electrons. The interaction between PETF and HYDA is of considerable interest, as PETF is the primary electron donor to HYDA and electron supply is one of the main limiting factors for H production on a commercial scale. Although there is no three dimensional structure of the PETF-HYDA complex available, protein variants, nuclear magnetic resonance titration studies, molecular dynamics and modelling have provided considerable insight into the residues essential for forming and maintaining the interaction. In this review, we discuss the most recent findings with regard to ferredoxin-HYDA interactions and the evolution of the various Chlamydomonas reinhardtii ferredoxin isoforms. Finally, we provide an outlook on new PETF-based biotechnological approaches for improved H production efficiencies.

Characterization of photosynthetic ferredoxin from the Antarctic alga Chlamydomonas sp. UWO241 reveals novel features of cold adaptation

“…S4). All UWO241 Fds were predicted to contain the [2Fe‐2S] binding domain and clustered within previously defined classes in green algae (Yang et al ., ; Sawyer & Winkler, ) and plants (Fukuyama, ; Atkinson et al ., ) (Fig. ).…”

“…Green algae and plants contain multiple Fd isoforms, which have different functions (Winkler et al, 2010;Peden et al, 2013;Sawyer & Winkler, 2017). We screened the UWO241 genome and identified eight genes encoding putative Fds (Table 2).…”

ManiNetCluster: A Manifold Learning Approach to Reveal the Functional Linkages Across Multiple Gene Networks

“…Within the 10 shared genes are FTSY, which has a demonstrated role in LHC assembly (Kirst et al, 2012) suggests the possibility of additional roles during the dark period. Another gene in this group is FDX7, encoding a predicted uncharacterized ferrodoxin (Sawyer and Winkler, 2017), suggestive of a role in both the light and dark periods for this protein also. The triad pattern shown in Figure 5C also suggests a functional link between WGCNA Light-Module 9 and WGCNA Dark-Module 14, which cannot be detected by WGCNA itself, since they have shared genes with a ManiNetCluster functional linkage module (Module 55).…”

Solvent dynamics play a decisive role in the complex formation of biologically relevant redox proteins

“…[1][2][3][4] Plant-type FDXs are small metalloproteins that usually have low redox potentials (À300 to À460 mV) and harbor [2Fe-2S]-clusters. [1][2][3][4][5][6][7][8] In the photosynthetic electron transport chain of the well characterized unicellular green algae Chlamydomonas reinhardtii, FDX1 (also known as PetF) transfers electrons from photosystem I (PSI) to the flavoenzyme ferredoxin-NADP + -reductase (FNR) to generate nicotinamide adenine dinucleotide phosphate (NADPH), an important energy carrier in most biological systems. Regardless of whether occurring in vivo under physiological conditions or in vitro, electron transfer reactions between two or more proteins require the formation of transient protein complexes.…”

“…15 Interestingly, despite the presence of at least 13 FDXisoforms in C. reinhardtii, which are similar in their sequence and share structural homology (B40% sequence similarity), only a few of these isoforms (including PetF, FDX2, and FDX7) show an interaction with FNR. 6,8 Most importantly, the relevant acidic amino acids (including D58 of PetF) are strictly conserved in FDX-isoforms 1-3. However, the fact that FDX3 is not able to interact with FNR indicates that the processes of molecular recognition and complex stabilization cannot be solely attributed to the function of individual amino acids as these patterns are mainly conserved in FDX isoforms.…”