1
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Synthesis of 1,4,5,8-tetraethyl-2,3,6,7-tetravinylporphyrin from a Knorr's pyrrole analogue. Tetrahedron 2017. [DOI: 10.1016/j.tet.2017.10.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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2
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Kanai Y, Harada A, Shibata T, Nishimura R, Namiki K, Watanabe M, Nakamura S, Yumoto F, Senda T, Suzuki A, Neya S, Yamamoto Y. Characterization of Heme Orientational Disorder in a Myoglobin Reconstituted with a Trifluoromethyl-Group-Substituted Heme Cofactor. Biochemistry 2017; 56:4500-4508. [DOI: 10.1021/acs.biochem.7b00457] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yuki Kanai
- Department
of Chemistry, University of Tsukuba, Tsukuba 305-8571, Japan
| | - Ayaka Harada
- Structural
Biology Research Center, Institute of Materials Structure Science, KEK/High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Tomokazu Shibata
- Department
of Chemistry, University of Tsukuba, Tsukuba 305-8571, Japan
| | - Ryu Nishimura
- Department
of Chemistry, University of Tsukuba, Tsukuba 305-8571, Japan
| | - Kosuke Namiki
- Department
of Chemistry, University of Tsukuba, Tsukuba 305-8571, Japan
| | - Miho Watanabe
- Department
of Chemistry, University of Tsukuba, Tsukuba 305-8571, Japan
| | - Shunpei Nakamura
- Department
of Chemistry, University of Tsukuba, Tsukuba 305-8571, Japan
| | - Fumiaki Yumoto
- Structural
Biology Research Center, Institute of Materials Structure Science, KEK/High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Toshiya Senda
- Structural
Biology Research Center, Institute of Materials Structure Science, KEK/High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Akihiro Suzuki
- Department
of Materials Engineering, National Institute of Technology, Nagaoka College, Nagaoka 940-8532, Japan
| | - Saburo Neya
- Department
of Physical Chemistry, Graduate School of Pharmaceutical Sciences, Chiba University, Chuoh-Inohana, Chiba 260-8675, Japan
| | - Yasuhiko Yamamoto
- Department
of Chemistry, University of Tsukuba, Tsukuba 305-8571, Japan
- Life
Science Center of Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba 305-8577, Japan
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3
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Neya S, Nagai M, Nagatomo S, Hoshino T, Yoneda T, Kawaguchi AT. Utility of heme analogues to intentionally modify heme-globin interactions in myoglobin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:582-588. [PMID: 26435388 DOI: 10.1016/j.bbabio.2015.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 09/12/2015] [Accepted: 09/25/2015] [Indexed: 01/01/2023]
Abstract
Myoglobin reconstitution with various synthetic heme analogues was reviewed to follow the consequences of modified heme-globin interactions. Utility of dimethyl sulfoxide as the solvent for water-insoluble hemes was emphasized. Proton NMR spectroscopy revealed that loose heme-globin contacts in the heme pocket eventually caused the dynamic heme rotation around the iron-histidine bond. The full rotational rate was estimated to be about 1400 s(-1) at room temperature for 1,4,5,8-tetramethylhemin. The X-ray analysis of the myoglobin containing iron porphine, the smallest heme without any side chains, showed that the original globin fold was well conserved despite the serious disruption of native heme-globin contacts. Comparison between the two myoglobins with static and rotatory prosthetic groups indicated that the oxygen and carbon monoxide binding profiles were almost unaffected by the heme motion. On the other hand, altered tetrapyrrole array of porphyrin dramatically changed the dissociation constant of oxygen from 0.0005 mm Hg of porphycene-myoglobin to ∞ in oxypyriporphyrin-myoglobin. Heme-globin interactions in myoglobin were also monitored with circular dichroism spectroscopy. The observation on several reconstituted protein revealed an unrecognized role of the propionate groups in protoheme. Shortening of heme 6,7-propionates to carboxylates resulted in almost complete disappearance of the positive circular dichroism band in the Soret region. The theoretical analysis suggested that the disappeared circular dichroism band reflected the cancellation effects between different conformers of the carboxyl groups directly attached to heme periphery. The above techniques were proposed to be applicable to other hemoproteins to create new biocatalysts. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson.
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Affiliation(s)
- Saburo Neya
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, Chiba University, Chuoh-Inohana, Chiba City, Chiba 260-8675, Japan.
| | - Masako Nagai
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-0003, Japan
| | - Shigenori Nagatomo
- Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Tyuji Hoshino
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, Chiba University, Chuoh-Inohana, Chiba City, Chiba 260-8675, Japan
| | - Tomoki Yoneda
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, Chiba University, Chuoh-Inohana, Chiba City, Chiba 260-8675, Japan
| | - Akira T Kawaguchi
- School of Medicine, Tokai University, Isehara, Kanagawa 259-1193, Japan
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4
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Nagai M, Kobayashi C, Nagai Y, Imai K, Mizusawa N, Sakurai H, Neya S, Kayanuma M, Shoji M, Nagatomo S. Involvement of Propionate Side Chains of the Heme in Circular Dichroism of Myoglobin: Experimental and Theoretical Analyses. J Phys Chem B 2015; 119:1275-87. [DOI: 10.1021/jp5086203] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- 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 920-0942, Japan
| | - Chika Kobayashi
- Department
of Frontier Bioscience, Faculty of Bioscience and Applied Chemistry, Hosei University, Koganei, Tokyo 184-8584, Japan
| | - Yukifumi Nagai
- Research
Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-0003, Japan
| | - Kiyohiro Imai
- Department
of Frontier Bioscience, Faculty of Bioscience and Applied Chemistry, Hosei University, Koganei, Tokyo 184-8584, Japan
| | - Naoki Mizusawa
- Research
Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-0003, Japan
- Department
of Frontier Bioscience, Faculty of Bioscience and Applied Chemistry, Hosei University, Koganei, Tokyo 184-8584, Japan
| | - Hiroshi Sakurai
- School
of Health Sciences, College of Medical, Pharmaceutical and Health
Sciences, Kanazawa University, Kanazawa 920-0942, Japan
| | - Saburo Neya
- Department
of Physical Chemistry, Graduate School of Pharmaceutical Sciences, Chiba University, Inohana, Chuo-Ku, Chiba 260-8675, Japan
| | - Megumi Kayanuma
- Department
of Computer Science, Graduate School of Systems and Information Engineering, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
| | - Mitsuo Shoji
- Department
of Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Shigenori Nagatomo
- Department
of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
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5
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Neya S. Dynamic motion and rearranged molecular shape of heme in myoglobin: structural and functional consequences. Molecules 2013; 18:3168-82. [PMID: 23478515 PMCID: PMC6269712 DOI: 10.3390/molecules18033168] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 03/07/2013] [Accepted: 03/07/2013] [Indexed: 11/16/2022] Open
Abstract
Myoglobin, a simple oxygen binding protein, was reconstituted with various types of synthetic hemes to manipulate the heme-globin interactions. From the paramagnetic NMR analysis, small heme was found to rotate rapidly about the iron-histidine bond upon. This is a novel and typical example for the fluctuation of protein. The dynamic NMR analysis indicated that the 360° rotational rate of a small heme was 1,400 s−1 at room temperature. The X-ray analyses revealed that the tertiary structure of globin containing the smallest heme was closely similar to that of native protein despite extensive destruction of the specific heme-globin interactions. The functional analyses of O2 binding showed that the loose heme-globin contacts do not significantly affect the oxygen binding. On the other hand, the rearrangement of tetrapyrrole array and the non-planar deformation in porphyrin ring significantly affect the functional properties of myoglobin. These results, taken together, indicate that the essential factors to regulate the myoglobin function are hidden under the molecular shape of prosthetic group rather than in the nonbonded heme-globin contacts.
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Affiliation(s)
- Saburo Neya
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, Chiba University, Chuoh-Inohana, Chiba City, Chiba 260-8675, Japan.
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6
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Koyama M, Neya S, Mizutani Y. Role of heme propionates of myoglobin in vibrational energy relaxation. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.09.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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Juillard S, Bondon A, Simonneaux G. Proton NMR study of myoglobin reconstituted with 3,7-diethyl-2,8-dimethyl iron porphyrin: Remarkable influence of peripheral substitution on heme rotation. J Inorg Biochem 2006; 100:1441-8. [PMID: 16766034 DOI: 10.1016/j.jinorgbio.2006.04.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Revised: 04/03/2006] [Accepted: 04/06/2006] [Indexed: 11/29/2022]
Abstract
The iron complex of 3,7-diethyl-2,8-dimethylporphyrin was incorporated into horse heart apomyoglobin to investigate the influence of peripheral substitution on artificial heme rotation. The hyperfine-shifted 1H NMR spectrum of the reconstituted deoxymyoglobin (rMb) revealed the proximal imidazole N-H resonance at 82.5 ppm to indicate the formation of the Fe--N (His93) bond. The pyrrole-protons of the hemin of myoglobin in the absence of external ligand appeared as four resonances between -10 and -18 ppm, indicating a mainly low-spin ferric hemin, with a ligated distal histidine (His64). This also indicates the lost of the symmetry of the hemin, according to an absence of free rotation of the prosthetic group. The 1H NMR spectrum of reconstituted rMbCO revealed a set of four pyrrole-protons and a set of four meso-protons. Accordingly, the prosthetic group without acid side chains interacts specifically with the surrounding globin showing a unique heme orientation in the 1H NMR time-scale, despite the presence of only four alkyl substituents on the porphine ring. This also suggests that two ethyl groups are large enough to avoid the free rotation movement of the heme.
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Affiliation(s)
- Sandrine Juillard
- Laboratoire de Chimie Organométallique et Biologique, UMR CNRS 6226, Campus de Beaulieu, Université de Rennes 1, 35042 Rennes, France
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Neya S, Imai K, Hiramatsu Y, Kitagawa T, Hoshino T, Hata M, Funasaki N. Significance of the Molecular Shape of Iron Corrphycene in a Protein Pocket. Inorg Chem 2006; 45:4238-42. [PMID: 16676986 DOI: 10.1021/ic0600679] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The iron complex of a new type of corrphycene bearing two ethoxycarbonyl (-CO2C2H5) groups on the bipyrrole moiety was introduced into apomyoglobin. The reconstituted ferric myoglobin has a coordinating water molecule that deprotonates to hydroxide with a pK(a) value of 7.3 and exhibits 3-10-fold higher affinities for anionic ligands when compared with a counterpart myoglobin with the same substituents on the dipyrroethene moiety. In the ferrous state, the oxygen affinity of the new myoglobin was decreased to 1/410 of the native protein. The anomalies in the ligand binding, notably dependent on the side-chain location, were interpreted in terms of a characteristic core shape of corrphycene that produces the longer and shorter Fe-N(pyrrole) bonds. The spin-state equilibrium analysis of the ferric azide myoglobin containing the new iron corrphycene supported the nonequivalence of the Fe-N(pyrrole) bonds. These results demonstrate that the trapezoidal molecular shape of corrphycene exerts functional significance when the iron complex is placed in a protein pocket.
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Affiliation(s)
- Saburo Neya
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, Chiba University, Inage-Yayoi, Chiba 263-8522, Japan.
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Bondarenko V, Wang J, Kalish H, Balch AL, La Mar GN. Solution 1H NMR study of the accommodation of the side chain of n-butyl-etiohemin-I incorporated into the active site of cyano-metmyoglobin. J Biol Inorg Chem 2005; 10:283-93. [PMID: 15821940 DOI: 10.1007/s00775-005-0640-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Accepted: 03/01/2005] [Indexed: 11/24/2022]
Abstract
In order to identify the most readily deformable portion of the heme pocket in myoglobin, equine myoglobin was reconstituted with a meso-n-butyl substituent on centrosymmetric etiohemin-I. Solution 1H NMR data for the low-spin iron(III) cyanide complex of oxidized myoglobin that include 2D nuclear Overhauser enhancement spectroscopy contacts, paramagnetic relaxation, and dipolar shifts resulting from magnetic anisotropy show that the heme binds uniquely to the iron in a manner that arranges the methyl and ethyl substituents on a given pyrrole in a clockwise manner when viewed from the proximal side, and with the n-butyl group seated at the canonical alpha-meso position of native protohemin-IX. The butyl group is oriented sharply toward the proximal side and its protein contacts demonstrate that it is oriented largely into the "xenon hole" in myoglobin. The location of the n-butyl group on the proximal side near the vacancies places it within the region found to be most flexible in molecular dynamics simulation. A small, counterclockwise rotation of the pyrrole N-Fe-N vector of n-butyl-etiohemin-I relative to that for native protohemin, indicated by both the prosthetic group methyl contact shift pattern and the prosthetic group contacts to heme pocket residues, is proposed to allow the xenon hole to accommodate better the n-butyl group. In contrast to previous work, which showed that a bulky polar substituent on etiohemin-I preferentially seats at the canonical gamma-meso position, the nonpolar n-butyl group selects the alpha-meso position.
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Affiliation(s)
- Vasyl Bondarenko
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA
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10
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Neya S, Imai K, Hori H, Ishikawa H, Ishimori K, Okuno D, Nagatomo S, Hoshino T, Hata M, Funasaki N. Iron hemiporphycene as a functional prosthetic group for myoglobin. Inorg Chem 2003; 42:1456-61. [PMID: 12611510 DOI: 10.1021/ic020504t] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The iron complex of hemiporphycene, a molecular hybrid of porphyrin with porphycene, was incorporated into the apomyoglobin pocket to examine ligand binding ability of the iron atom in the novel porphyrinoid. Apomyoglobin was successfully coupled with a stoichiometric amount of ferric hemiporphycene to afford the reconstituted myoglobin equipped with the iron coordination structure of native protein. Cyanide, imidazole, and fluoride coordinated to the ferric protein with affinities comparable with those for native myoglobin. The ferrous myoglobin was functionally active to bind O(2) and CO reversibly at pH 7.4 and 20 degrees C. The O(2) affinity is 12-fold higher than that of native myoglobin while the CO affinity is slightly lower, suggesting decreased discrimination between O(2) and CO in the heme pocket. The functional anomaly was interpreted to reflect increased sigma-bonding character in the Fe(II)-O(2) bond. In contrast with 6-coordinate native NO protein, the NO myoglobin containing ferrous hemiporphycene is in a mixed 5- and 6-coordinate state. This observation suggests that the in-plane configuration of the iron atom in hemiporphycene is destabilized by NO. Influence of the core deformation was also detected with both the infrared absorption for the ferrous CO derivative and electron paramagnetic resonance for ferric imidazole complex. Anomalies in the ferric and ferrous derivatives were ascribed to the modified iron-N(pyrrole) interactions in the asymmetric metallo core of hemiporphycene.
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Affiliation(s)
- Saburo Neya
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, Chiba University, Inage-Yayoi, Japan.
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Neya S, Nakamura M, Imai K, Funasaki N. Functional analysis of the iron(II) etiocorrphycene incorporated in the myoglobin heme pocket. Chem Pharm Bull (Tokyo) 2001; 49:345-6. [PMID: 11253930 DOI: 10.1248/cpb.49.345] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The iron(III) complex of 2,7,12,17-tetraethyl-3,6,11,18-tetra-methylcorrphycene, an isomeric heme, was complexed with apomyoglobin to examine the ligand binding ability of the novel macrocycle under physiological conditions. The reconstituted holoprotein was found to be functionally active at pH 7.4 and 20 degrees C and to bind oxygen and carbon monoxide reversibly with a half-saturation pressure at 6.7 and 3.5mmHg, respectively. Equilibrium affinities for these ligands are one to two orders of magnitude lower than those reported for native myoglobin. The functional anomaly was ascribed to the geometric and electronic strain on the iron(II) atom in the trapezoidal coordination core of corrphycene.
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Affiliation(s)
- S Neya
- Department of Physical Chemistry, Kyoto Pharmaceutical University, Japan.
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12
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Mie Y, Sonoda K, Kishita M, Krestyn E, Neya S, Funasaki N, Taniguchi I. Effect of rapid heme rotation on electrochemistry of myoglobin. Electrochim Acta 2000. [DOI: 10.1016/s0013-4686(00)00366-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Neya S, Nakamura M, Imai K, Hori H, Funasaki N. Functional comparison of the myoglobins reconstituted with symmetric deuterohemes. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1296:245-9. [PMID: 8814232 DOI: 10.1016/0167-4838(96)00078-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Deuterohemins III and XIII were coupled with apomyoglobin to examine the influence of the modified heme-globin contacts on the functions of the reconstituted holoproteins. Owing to the molecular symmetry of the prosthetic groups, the resultant proteins are free from the heme orientational disorder. The coordination structures of the two reconstituted myoglobins were found to be normal and closely similar to each other. The equilibrium ligand bindings also resembled with each other in both ferric and ferrous states. The results demonstrate that the different local heme-globin contacts affect the structure and function of the reconstituted myoglobins only slightly. The results therefore suggest that the two asymmetric deuteroheme IX isomers, which are inverted about the alpha, gamma-meso carbon axis of the heme, also exhibit very similar functions in myoglobin.
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Affiliation(s)
- S Neya
- Department of Physical Chemistry, Kyoto Pharmaceutical University, Japan
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14
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Neya S, Kaku T, Funasaki N, Shiro Y, Iizuka T, Imai K, Hori H. Novel ligand binding properties of the myoglobin substituted with monoazahemin. J Biol Chem 1995; 270:13118-23. [PMID: 7768907 DOI: 10.1074/jbc.270.22.13118] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The iron complex of alpha-azamesoporphyrin XIII was combined with apomyoglobin to investigate influence of the meso nitrogen on ligand binding properties in the reconstituted protein. Stoichiometric complex formation between the two components was confirmed, and conservation of the native coordination structures in the resultant myoglobin was established with spectroscopic criteria and apparently normal ligand binding. The visible absorption spectra of various ferric and ferrous derivatives are characteristic with less intense Soret peaks and enhanced visible bands. The electron paramagnetic resonance spectrum with g = 5.2 suggests an anomalous intermediate spin (S = 3/2) character for the aquomet protein. The oxygen affinity of reduced azaheme myoglobin, 0.010 mm Hg, is 50 times larger than that of the native myoglobin. In addition, azaheme myoglobin forms stable complexes with imidazole, pyridine, or cyanide in ferrous state. All of these new properties were consistently explained in terms of stronger equatorial ligand field of the heme iron in a narrower coordination cavity. Similarities of azaheme to verdoheme were also pointed out.
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Affiliation(s)
- S Neya
- Department of Physical Chemistry, Kyoto Pharmaceutical University, Japan
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15
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Neya S, Funasaki N, Shiro Y, Iizuka T, Imai K. Consequence of rapid heme rotation to the oxygen binding of myoglobin. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1208:31-7. [PMID: 8086436 DOI: 10.1016/0167-4838(94)90156-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The myoglobin complexed with octamethylhemin was prepared. The visible absorption profiles are typical of general alkylhemin-substituted myoglobins, suggesting normal insertion of the hemin into the hydrophobic cavity. The NMR spectra of various ferric proteins were anomalous, without clearly resolved signals from the prosthetic group, most probably reflecting rapid heme rotation about the iron-histidine bond. The equilibrium and kinetic oxygen bindings were measured to examine the functional significance of the heme motion. Functional comparison with the myoglobin having immobile hemin indicates that rotation of the octamethylheme negligibly affects the myoglobin function. The results suggest that neither the heme peripheral contacts nor the proximal imidazole orientation about the heme normal is the dominant factor to control myoglobin function.
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Affiliation(s)
- S Neya
- Department of Physical Chemistry, Kyoto Pharmaceutical University, Japan
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16
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Neya S, Funasaki N, Sato T, Igarashi N, Tanaka N. Structural analysis of the myoglobin reconstituted with iron porphine. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)52962-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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