Fig. 1.

Screening for Fd-HydA expressing clones. C. reinhardtii hydA _1,2 double mutant cells were transformed with Fd-HydA either under a Hsp70-RbcS2 or b psaD promoter. The transformants were screened for gene expression using the H₂ sensitive R. capsulatus screen. Chlorophyll fluorescence of the algae is shown in red whereas dark halation represents GFP produced by R. capsulatus upon H₂ presence. The wt strain CC-124 (white circle) and hydA _1,2 double mutant (blue circle) clones were used as positive and negative controls, respectively. The highest Fd-HydA expressing clones (1D4 for Hsp70-RbcS2 and P6 for psaD) are circled with purple and yellow, respectively. c Immunoblot analysis for detection of Fd-HydA expression. Soluble proteins (75 µg of each) from 1D4 (lane 1) and P6 (lane 2) were loaded on 4-12 % Bis–Tris PAGE (Life Technologies) and probed with rabbit polyclonal HydA1/2 antibodies. C. reinhardtii Fd-HydA (10 ng) expressed heterologously and purified from E. coli (co-loaded with soluble protein from the hydA _1,2 mutant) was used as positive control (lane 4)