Cloning and characterization of two flavohemoglobins from Aspergillus oryzae.
Two flavohemoglobin (FHb) genes, fhb1 and fhb2, were cloned from Aspergillus oryzae. The amino acid sequences of the deduced FHb1 and FHb2 showed high identity to other FHbs except for the predicted mitochondrial targeting signal in the N-terminus of FHb2. The recombinant proteins displayed absorption spectra similar to those of other FHbs. FHb1 and FHb2 were estimated to be a monomer and a dimer in solution, respectively. Both of the isozymes exhibit high NO dioxygenase (NOD) activity. FHb1 utilizes either NADH or NADPH as an electron donor, whereas FHb2 can only use NADH. These results suggest that FHb1 and FHb2 are fungal counterparts of bacterial FHbs and act as NO detoxification enzymes in the cytosol and mitochondria, respectively. This study is the first to show that a microorganism contains two isozymes of FHb and that intracellular localization of the isozymes could differ.
Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Shengmin
S
Zhou
Shinya
S
Fushinobu
Yoshito
Y
Nakanishi
Sang-Wan
SW
Kim
Takayoshi
T
Wakagi
Hirofumi
H
Shoun
D000595:Amino Acid Sequence; D001236:Aspergillus oryzae / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D006420:Hemeproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
D006420:Hemeproteins; D011994:Recombinant Proteins