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Nagatomo S, Nagai M, Kitagawa T. Structural origin of cooperativity in human hemoglobin: a view from different roles of α and β subunits in the α2β2 tetramer. Biophys Rev 2022; 14:483-498. [PMID: 35528033 PMCID: PMC9043147 DOI: 10.1007/s12551-022-00945-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 03/14/2022] [Indexed: 11/26/2022] Open
Abstract
This mini-review, mainly based on our resonance Raman studies on the structural origin of cooperative O2 binding in human adult hemoglobin (HbA), aims to answering why HbA is a tetramer consisting of two α and two β subunits. Here, we focus on the Fe-His bond, the sole coordination bond connecting heme to a globin. The Fe-His stretching frequencies reflect the O2 affinity and also the magnitude of strain imposed through globin by inter-subunit interactions, which is the origin of cooperativity. Cooperativity was first explained by Monod, Wyman, and Changeux, referred to as the MWC theory, but later explained by the two tertiary states (TTS) theory. Here, we related the higher-order structures of globin observed mainly by vibrational spectroscopy to the MWC theory. It became clear from the recent spectroscopic studies, X-ray crystallographic analysis, and mutagenesis experiments that the Fe-His bonds exhibit different roles between the α and β subunits. The absence of the Fe-His bond in the α subunit in some mutant and artificial Hbs inhibits T to R quaternary structural change upon O2 binding. However, its absence from the β subunit in mutant and artificial Hbs simply enhances the O2 affinity of the α subunit. Accordingly, the inter-subunit interactions between α and β subunits are nonsymmetric but substantial for HbA to perform cooperative O2 binding.
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Affiliation(s)
- Shigenori Nagatomo
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571 Japan
| | - Masako Nagai
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, 184-0003 Japan
- School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa 920-0942 Japan
| | - Teizo Kitagawa
- Graduate School of Life Science, Picobiology Institute, University of Hyogo, Kouto, Kamigori, Ako-gun Hyogo, 678-1297 Japan
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Nagatomo S, Saito K, Yamamoto K, Ogura T, Kitagawa T, Nagai M. Heterogeneity between Two α Subunits of α2β2 Human Hemoglobin and O2 Binding Properties: Raman, 1H Nuclear Magnetic Resonance, and Terahertz Spectra. Biochemistry 2017; 56:6125-6136. [DOI: 10.1021/acs.biochem.7b00733] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shigenori Nagatomo
- Department
of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Kazuya Saito
- Department
of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Kohji Yamamoto
- Research
Center for Development of Far-Infrared Region, University of Fukui, Fukui, Fukui 910-8507, Japan
| | - Takashi Ogura
- Picobiology
Institute, Graduate School of Life Science, University of Hyogo, RSC-UH Leading
Program Center, Sayo, Sayo-gun, Hyogo 679-5148, Japan
| | - Teizo Kitagawa
- Picobiology
Institute, Graduate School of Life Science, University of Hyogo, Kouto, Kamigori, Ako-gun, Hyogo 678-1297, Japan
| | - Masako Nagai
- Research
Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-0003, Japan
- School
of
Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa 920-0942, Japan
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Nagatomo S, Nagai Y, Aki Y, Sakurai H, Imai K, Mizusawa N, Ogura T, Kitagawa T, Nagai M. An Origin of Cooperative Oxygen Binding of Human Adult Hemoglobin: Different Roles of the α and β Subunits in the α2β2 Tetramer. PLoS One 2015; 10:e0135080. [PMID: 26244770 PMCID: PMC4526547 DOI: 10.1371/journal.pone.0135080] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 07/17/2015] [Indexed: 02/02/2023] Open
Abstract
Human hemoglobin (Hb), which is an α2β2 tetramer and binds four O2 molecules, changes its O2-affinity from low to high as an increase of bound O2, that is characterized by 'cooperativity'. This property is indispensable for its function of O2 transfer from a lung to tissues and is accounted for in terms of T/R quaternary structure change, assuming the presence of a strain on the Fe-histidine (His) bond in the T state caused by the formation of hydrogen bonds at the subunit interfaces. However, the difference between the α and β subunits has been neglected. To investigate the different roles of the Fe-His(F8) bonds in the α and β subunits, we investigated cavity mutant Hbs in which the Fe-His(F8) in either α or β subunits was replaced by Fe-imidazole and F8-glycine. Thus, in cavity mutant Hbs, the movement of Fe upon O2-binding is detached from the movement of the F-helix, which is supposed to play a role of communication. Recombinant Hb (rHb)(αH87G), in which only the Fe-His in the α subunits is replaced by Fe-imidazole, showed a biphasic O2-binding with no cooperativity, indicating the coexistence of two independent hemes with different O2-affinities. In contrast, rHb(βH92G), in which only the Fe-His in the β subunits is replaced by Fe-imidazole, gave a simple high-affinity O2-binding curve with no cooperativity. Resonance Raman, 1H NMR, and near-UV circular dichroism measurements revealed that the quaternary structure change did not occur upon O2-binding to rHb(αH87G), but it did partially occur with O2-binding to rHb(βH92G). The quaternary structure of rHb(αH87G) appears to be frozen in T while its tertiary structure is changeable. Thus, the absence of the Fe-His bond in the α subunit inhibits the T to R quaternary structure change upon O2-binding, but its absence in the β subunit simply enhances the O2-affinity of α subunit.
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Affiliation(s)
- Shigenori Nagatomo
- Department of Chemistry, University of Tsukuba, Tsukuba, Ibaraki, Japan
- * E-mail: (SN); (TK); (MN)
| | - Yukifumi Nagai
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan,3 School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan,4 Department of Frontier Biosciences, Hosei University, Koganei, Tokyo, Japan,5 Picobiology Institute, Graduate School of Life Science, University of Hyogo, RSC-UH Leading Program Center, Sayo, Sayo-gun, Hyogo, Japan
| | - Yayoi Aki
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan,3 School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan,4 Department of Frontier Biosciences, Hosei University, Koganei, Tokyo, Japan,5 Picobiology Institute, Graduate School of Life Science, University of Hyogo, RSC-UH Leading Program Center, Sayo, Sayo-gun, Hyogo, Japan
| | - Hiroshi Sakurai
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan,3 School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan,4 Department of Frontier Biosciences, Hosei University, Koganei, Tokyo, Japan,5 Picobiology Institute, Graduate School of Life Science, University of Hyogo, RSC-UH Leading Program Center, Sayo, Sayo-gun, Hyogo, Japan
| | - Kiyohiro Imai
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan,3 School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan,4 Department of Frontier Biosciences, Hosei University, Koganei, Tokyo, Japan,5 Picobiology Institute, Graduate School of Life Science, University of Hyogo, RSC-UH Leading Program Center, Sayo, Sayo-gun, Hyogo, Japan
| | - Naoki Mizusawa
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan,3 School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan,4 Department of Frontier Biosciences, Hosei University, Koganei, Tokyo, Japan,5 Picobiology Institute, Graduate School of Life Science, University of Hyogo, RSC-UH Leading Program Center, Sayo, Sayo-gun, Hyogo, Japan
| | - Takashi Ogura
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan,3 School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan,4 Department of Frontier Biosciences, Hosei University, Koganei, Tokyo, Japan,5 Picobiology Institute, Graduate School of Life Science, University of Hyogo, RSC-UH Leading Program Center, Sayo, Sayo-gun, Hyogo, Japan
| | - Teizo Kitagawa
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan,3 School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan,4 Department of Frontier Biosciences, Hosei University, Koganei, Tokyo, Japan,5 Picobiology Institute, Graduate School of Life Science, University of Hyogo, RSC-UH Leading Program Center, Sayo, Sayo-gun, Hyogo, Japan
- * E-mail: (SN); (TK); (MN)
| | - Masako Nagai
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan,3 School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan,4 Department of Frontier Biosciences, Hosei University, Koganei, Tokyo, Japan,5 Picobiology Institute, Graduate School of Life Science, University of Hyogo, RSC-UH Leading Program Center, Sayo, Sayo-gun, Hyogo, Japan
- * E-mail: (SN); (TK); (MN)
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