TY - JOUR
T1 - O 2-stable membrane-bound [NiFe]hydrogenase from a newly isolated Citrobacter sp. S-77
AU - Eguchi, Shigenobu
AU - Yoon, Ki Seok
AU - Ogo, Seiji
N1 - Funding Information:
This work was supported by World Premier International Research Center Initiative (WPI) , grants-in-aid: 18065017 (Chemistry of Concerto Catalysis), 19205009 and 23655053 , the Global COE Program, “Science for Future Molecular Systems” from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan and the Basic Research Programs CREST Type, “Development of the Foundation for Nano-Interface Technology” from Japan Science and Technology Agency (JST), Japan.
PY - 2012/11
Y1 - 2012/11
N2 - Hydrogenases are of great interest due to their potential use in H 2-based technology. However, most hydrogenases are highly sensitive to O 2, which have been the major bottleneck in hydrogenase studies. Here we report an O 2-stable membrane-bound [NiFe]hydrogenase (MBH) purified from a newly isolated strain, S-77. According to the 16S rRNA gene sequence and phylogenetic analysis of the strain S-77, it belongs to the genus of Citrobacter. In vitro experiments using the cytoplasmic membrane of strain S-77 suggested that a cytochrome b acts as the physiological electron acceptor of the MBH. The purified MBH was composed of a dimer of heterodimers, consisting of two distinct subunits with the molecular weights of 58.5 and 38.5 kDa. The enzyme showed a specific activity for H 2-oxidation of 661U/mg, which is 35-fold greater than that for H 2-production of 18.7U/mg. Notably, the MBH showed a remarkable O 2-stability, maintaining almost 95% of its original activity even after incubation for 30 h in air at 4°C. These results suggest that the O 2-stable MBH may play an important role in the H 2-metabolic pathway under the aerobic conditions of Citrobacter sp. S-77. This is the first report of the purification and biochemical characterization of an O 2-stable MBH from the genus of Citrobacter.
AB - Hydrogenases are of great interest due to their potential use in H 2-based technology. However, most hydrogenases are highly sensitive to O 2, which have been the major bottleneck in hydrogenase studies. Here we report an O 2-stable membrane-bound [NiFe]hydrogenase (MBH) purified from a newly isolated strain, S-77. According to the 16S rRNA gene sequence and phylogenetic analysis of the strain S-77, it belongs to the genus of Citrobacter. In vitro experiments using the cytoplasmic membrane of strain S-77 suggested that a cytochrome b acts as the physiological electron acceptor of the MBH. The purified MBH was composed of a dimer of heterodimers, consisting of two distinct subunits with the molecular weights of 58.5 and 38.5 kDa. The enzyme showed a specific activity for H 2-oxidation of 661U/mg, which is 35-fold greater than that for H 2-production of 18.7U/mg. Notably, the MBH showed a remarkable O 2-stability, maintaining almost 95% of its original activity even after incubation for 30 h in air at 4°C. These results suggest that the O 2-stable MBH may play an important role in the H 2-metabolic pathway under the aerobic conditions of Citrobacter sp. S-77. This is the first report of the purification and biochemical characterization of an O 2-stable MBH from the genus of Citrobacter.
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U2 - 10.1016/j.jbiosc.2012.05.018
DO - 10.1016/j.jbiosc.2012.05.018
M3 - Article
C2 - 22721689
AN - SCOPUS:84866364900
VL - 114
SP - 479
EP - 484
JO - Journal of Bioscience and Bioengineering
JF - Journal of Bioscience and Bioengineering
SN - 1389-1723
IS - 5
ER -