Mass spectrometric identification of lysine residues of heme oxygenase-1 that are involved in its interaction with NADPH-cytochrome P450 reductase.
The lysine residues of rat heme oxygenase-1 (HO-1) were acetylated by acetic anhydride in the absence and presence of NADPH-cytochrome P450 reductase (CPR) or biliverdin reductase (BVR). Nine acetylated peptides were identified by MALDI-TOF mass spectrometry in the tryptic fragments obtained from HO-1 acetylated without the reductases (referred to as the fully acetylated HO-1). The presence of CPR prevented HO-1 from acetylation of lysine residues, Lys-149 and Lys-153, located in the F-helix. The heme degradation activity of the fully acetylated HO-1 in the NADPH/CPR-supported system was significantly reduced, whereas almost no inactivation was detected in HO-1 in the presence of CPR, which prevented acetylation of Lys-149 and Lys-153. On the other hand, the presence of BVR showed no protective effect on the acetylation of HO-1. The interaction of HO-1 with CPR or BVR is discussed based on the acetylation pattern and on molecular modeling.
Higashimoto
Yuichiro
Y
Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan.
Sugishima
Masakazu
M
Sato
Hideaki
H
Sakamoto
Hiroshi
H
Fukuyama
Keiichi
K
Palmer
Graham
G
Noguchi
Masato
M
D000595:Amino Acid Sequence; D001665:Binding Sites; D003198:Computer Simulation; D004789:Enzyme Activation; D006419:Heme Oxygenase (Decyclizing) / Q000737:chemistry* / Q000648:ultrastructure*; D008239:Lysine / Q000737:chemistry*; D013058:Mass Spectrometry; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009251:NADPH-Ferrihemoprotein Reductase / Q000737:chemistry* / Q000648:ultrastructure*; D010449:Peptide Mapping; D011485:Protein Binding; D025941:Protein Interaction Mapping
D006419:Heme Oxygenase (Decyclizing); C491523:Hmox1 protein, rat; D009251:NADPH-Ferrihemoprotein Reductase; D008239:Lysine