Characterizing the Anaerobic Response of Chlamydomonas reinhardtii by Quantitative Proteomics

Abstract

The versatile metabolism of the green alga Chlamydomonas reinhardtii is reflected in its complex response to anaerobic conditions. The anaerobic response is also remarkable in the context of renewable energy because C. reinhardtii is able to produce hydrogen under anaerobic conditions. To identify proteins involved during anaerobic acclimation as well as to localize proteins and pathways to the powerhouses of the cell, chloroplasts and mitochondria from C. reinhardtii in aerobic and anaerobic (induced by 8 h of argon bubbling) conditions were isolated and analyzed using comparative proteomics. A total of 2315 proteins were identified. Further analysis based on spectral counting clearly localized 606 of these proteins to the chloroplast, including many proteins of the fermentative metabolism. Comparative quantitative analyses were performed with the chloroplast-localized proteins using stable isotopic labeling of amino acids (

A Mutant in theADH1Gene ofChlamydomonas reinhardtiiElicits Metabolic Restructuring during Anaerobiosis

“…Interestingly, an AdhE/ADH1 homolog is not present in the majority of prokaryotes, and among the eukaryotes, it has only been identified in a few amitochondriate protists and some green algae (Atteia et al, 2003(Atteia et al, , 2006. In the alga Polytomella, the ADHE protein was localized to the mitochondrion (Atteia et al, 2003), while in Chlamydomonas, ADH1 was found to be present in chloroplasts (Terashima et al, 2010). This difference in subcellular location, which could be explained by differences in targeting sequences located at the N terminus of the enzyme, may create differences in the intracellular trafficking of metabolites.…”

“…Based on sequence similarities with E. coli AdhE, the dual-function Chlamydomonas ADH1 protein has been suggested to operate downstream of PFL1, where it would reduce acetyl-CoA to acetaldehyde and then to ethanol, resulting in the regeneration of two molecules of NAD + per molecule of acetyl-CoA (Mus et al, 2007;Terashima et al, 2010;Grossman et al, 2011; Fig. 1).…”

Induction of Photosynthetic Carbon Fixation in Anoxia Relies on Hydrogenase Activity and Proton-Gradient Regulation-Like1-Mediated Cyclic Electron Flow in Chlamydomonas reinhardtii

“…Under anoxia, lack of ATP synthesis by F 1 F O ATP synthase (EC 3.6.3.14) due to the absence of mitochondrial respiration is compensated by the activity of various plant-and bacterial-type fermentative enzymes that drive a sustained glycolytic activity (Mus et al, 2007;Terashima et al, 2010;Grossman et al, 2011;Yang et al, 2014). In C. reinhardtii, upstream glycolytic enzymes, including the reversible glyceraldehyde 3-P dehydrogenase, are located in the chloroplast (Johnson and Alric, 2012).…”

Role of Type 2 NAD(P)H Dehydrogenase NdbC in Redox Regulation of Carbon Allocation in Synechocystis

“…However, NDA2 showed higher affinity to NADH than NADPH and had FMN as a cofactor instead of the more common FAD. Another NDH-2 enzyme, NDA3, has been localized to C. reinhardtii chloroplasts (Terashima et al, 2010). Physcomitrella patens has six NDH-2 genes, and the products of three of them are targeted to chloroplasts (Xu et al, 2013).…”