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A single mutation converts Alr5027 from cyanobacteria Nostoc sp. PCC 7120 to a heme-binding protein with heme-degrading ability
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| Title: | A single mutation converts Alr5027 from cyanobacteria Nostoc sp. PCC 7120 to a heme-binding protein with heme-degrading ability |
| Authors: | Dojun, Nobuhiko Browse this author | | Muranishi, Kazuyoshi Browse this author | | Ishimori, Koichiro Browse this author →KAKEN DB | | Uchida, Takeshi Browse this author →KAKEN DB |
| Keywords: | Cyanobacteria | | Vibrio cholerae | | Heme oxygenase | | Redox protein | | Enzyme | | Heme |
| Issue Date: | Feb-2020 |
| Publisher: | Elsevier |
| Journal Title: | Journal of Inorganic Biochemistry |
| Volume: | 203 |
| Start Page: | 110916 |
| Publisher DOI: | 10.1016/j.jinorgbio.2019.110916 |
| Abstract: | HutZ from Vibrio cholerae (VcHutZ) is a dimeric protein that catalyzes oxygen-dependent degradation of heme. The reaction mechanism is the same as that of canonical heme oxygenase (HO), but the structure of HutZ is quite different from that of HO. Thus, we postulate that HutZ has evolved via a different pathway from that of HO. Alr5027 from cyanobacteria possessing proteins potentially related to ancestral proteins utilizing O2 in enzymatic reactions is homologous to HutZ family proteins (67% similarity), but the heme axial ligand of HutZ is not conserved in Alr5027. To investigate whether Alr5027 can bind and degrade heme, we expressed Alr5027 in Escherichia coli and purified it. Although Alr5027 did not bind heme, replacement of Lys164, corresponding to the heme axial ligand of HutZ, with histidine conferred heme-binding capability. The K164H mutant produced verdoheme in the reaction with H2O2, indicating acquisition of heme-degradation ability. Among the mutants, the K164H mutant produced verdoheme most efficiently. Although the K164H mutant did not degrade heme through ascorbic acid, biliverdin, the final product of VcHutZ, was formed by treatment of verdoheme with ascorbic acid. An analysis of Trp103 fluorescence indicated elongation of the distance between protomers in this mutant compared with VcHutZ—the probable cause of the inefficiency of ascorbic acid-supported heme-degradation activity. Collectively, our findings indicate that a single lysine-to-histidine mutation converted Alr5027 to a heme-binding protein that can form verdoheme through H2O2, suggesting that HutZ family proteins have acquired the heme-degradation function through molecular evolution from an ancestor protein of Alr5027. |
| Rights: | ©2019, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ | | http://creativecommons.org/licenses/by-nc-nd/4.0/ |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/83251 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 内田 毅
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