TY - JOUR
T1 - The in-vitro enhancement of FeFe hydrogenase activity by superoxide dismutase
AU - Ben Zvi, Oren
AU - Yacoby, Iftach
N1 - Publisher Copyright:
© 2016 Hydrogen Energy Publications LLC
PY - 2016/10/19
Y1 - 2016/10/19
N2 - H2 producing micro-algae such as Chlamydomonas reinhardtii (C. reinhardtii), express the strictly anaerobic enzyme FeFe-hydrogenase (HydA). In this study, we examined whether superoxide dismutase (SOD), an antioxidant, can protect HydA under aerobic conditions. We conducted in-vitro assays using purified enzymes, to analyze the activity of HydA in the presence or absence of SOD. We observed that SOD enhances HydA activity both in the presence and absence of oxygen, showing that the SOD effect on HydA activity is not strictly oxygen dependent. Furthermore, we found that SOD boosts Ferredoxin-NADP+-oxidoreductase (FNR) NDAP+ reduction but not NADPH oxidation i.e. diaphorase activity. Thus, suggesting a mechanism involving proton transfer rather than electron transfer. Based on these findings, we constructed a HydA-SOD fusion protein that further boosted hydrogen production by HydA. The HydA-SOD photosynthetic activity was enhanced by 300%, reaching 700 μmol H2 (mg [chl] hr)−1, which is the fastest photosynthetic rate ever reported for an algal HydA.
AB - H2 producing micro-algae such as Chlamydomonas reinhardtii (C. reinhardtii), express the strictly anaerobic enzyme FeFe-hydrogenase (HydA). In this study, we examined whether superoxide dismutase (SOD), an antioxidant, can protect HydA under aerobic conditions. We conducted in-vitro assays using purified enzymes, to analyze the activity of HydA in the presence or absence of SOD. We observed that SOD enhances HydA activity both in the presence and absence of oxygen, showing that the SOD effect on HydA activity is not strictly oxygen dependent. Furthermore, we found that SOD boosts Ferredoxin-NADP+-oxidoreductase (FNR) NDAP+ reduction but not NADPH oxidation i.e. diaphorase activity. Thus, suggesting a mechanism involving proton transfer rather than electron transfer. Based on these findings, we constructed a HydA-SOD fusion protein that further boosted hydrogen production by HydA. The HydA-SOD photosynthetic activity was enhanced by 300%, reaching 700 μmol H2 (mg [chl] hr)−1, which is the fastest photosynthetic rate ever reported for an algal HydA.
KW - Fusion enzyme
KW - Hydrogenase
KW - Mehler reaction
KW - Micro-algae
KW - Photosystem-I
KW - Superoxide dismutase
UR - http://www.scopus.com/inward/record.url?scp=84995553628&partnerID=8YFLogxK
U2 - 10.1016/j.ijhydene.2016.07.013
DO - 10.1016/j.ijhydene.2016.07.013
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AN - SCOPUS:84995553628
VL - 41
SP - 17274
EP - 17282
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
SN - 0360-3199
IS - 39
ER -