Three distinct Arabidopsis hemoglobins exhibit peroxidase-like activity and differentially mediate nitrite-dependent protein nitration.
All plants examined to date possess non-symbiotic hemoglobin whose physiological role remains unclear. The present study explored the catalytic function of three representative classes of the plant hemoglobin from Arabidopsis thaliana: AtGLB1, AtGLB2, and AtGLB3. Purified recombinant proteins of these hemoglobins displayed hydrogen peroxide-dependent oxidation of several peroxidase substrates that was sensitive to cyanide, revealing intrinsic peroxidase-like activity. In the presence of nitrite and hydrogen peroxide, AtGLB1 was the most efficient at mediating tyrosine nitration of its own and other proteins via the formation of reactive nitrogen species as a result of nitrite oxidation. AtGLB1 mRNA significantly accumulated in Arabidopsis seedlings exposed to nitrite, supporting the physiological relevance of its function to nitrite and nitrite-derived reactive nitrogen species.
Department of Biological Science, Faculty of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan. ahkkao@hiroshima-u.ac.jp
Atsushi
A
Sakamoto
Sho-Hei
SH
Sakurao
Keiko
K
Fukunaga
Toshiyuki
T
Matsubara
Manami
M
Ueda-Hashimoto
Shigefumi
S
Tsukamoto
Misa
M
Takahashi
Hiromichi
H
Morikawa
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D006454:Hemoglobins / Q000235:genetics / Q000378:metabolism*; D015151:Immunoblotting; D009566:Nitrates / Q000378:metabolism*; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D029681:Arabidopsis Proteins; D006454:Hemoglobins; D009566:Nitrates; D012333:RNA, Messenger; D011994:Recombinant Proteins; D010544:Peroxidases