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Degtyarenko I, Biarnés X, Nieminen RM, Rovira C. Density-functional molecular dynamics studies of biologically relevant iron and cobalt complexes with macrocyclic ligands. Coord Chem Rev 2008. [DOI: 10.1016/j.ccr.2007.10.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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2
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Unno M, Matsui T, Ikeda-Saito M. Structure and catalytic mechanism of heme oxygenase. Nat Prod Rep 2007; 24:553-70. [PMID: 17534530 DOI: 10.1039/b604180a] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Masaki Unno
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
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3
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Degtyarenko I, Nieminen RM, Rovira C. Structure and dynamics of dioxygen bound to cobalt and iron heme. Biophys J 2006; 91:2024-34. [PMID: 16751243 PMCID: PMC1557552 DOI: 10.1529/biophysj.106.083048] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this study we use ab initio molecular dynamics simulations to analyze the structure and dynamics of the oxygen ligand in models of the oxymyoglobin active site and its cobalt-substituted analog. Our calculations are performed for iron-porphyrin and cobalt-porphyrin complexes with imidazole and oxygen as axial ligands, and we investigate the effect of the distal histidine in the structure and dynamics of the metal-oxygen unit (MeO(2), Me = Fe, Co). We find that the interaction between the distal histidine and the oxygen ligand is stronger for the cobalt complex than for the iron one, consistent with the superoxide ion character of the bound O(2). The dynamics of the O(2) ligand can be described as oscillations of the O-O axis projection on the porphyrin plane within a porphyrin quadrant combined with frequent jumps from one quadrant to another. However, the ligand motion is significantly faster for CoO(2) compared to FeO(2). As a result, the iron complex shows localized ligand sites, whereas for cobalt several configurations are possible. This gives support to the highly dynamic motion of the oxygen ligand found in several experiments on cobalt oxymyoglobin and model complexes and underlines the higher mobility of the CoO(2) fragment compared to FeO(2).
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Affiliation(s)
- Ivan Degtyarenko
- Laboratory of Physics, Helsinki University of Technology, FIN-02015 HUT, Finland
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4
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Felber B, Diederich F. Synthesis of Dendritic Metalloporphyrins withDistal H-Bond Donors as Model Systems for Hemoglobin. Helv Chim Acta 2005. [DOI: 10.1002/hlca.200490288] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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5
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Hori H, Masuya F, Dou Y, Ikeda-Saito M. EPR studies on the photoinduced intermediates of NO complexes in recombinant ferric-Mb trapped at low temperatures. J Inorg Biochem 2000; 82:181-7. [PMID: 11132625 DOI: 10.1016/s0162-0134(00)00143-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The nitrosyl complex of ferric myoglobin is EPR-silent. Upon photolysis at low temperatures, the photoinduced intermediates trapped in the distal heme cavity exhibit new EPR spectra due to the interaction between the photodissociated NO (S=1/2) and the ferric high spin heme (S=5/2). In order to elucidate the effect of distal E7 (His64) and E11 (Val68) mutations upon the electronic structure of the metal center, its immediate environment, and its interaction with the photodissociated NO, EPR spectra of the photoproducts of the NO complexes of recombinant ferric Mb mutants were measured at 5 K. EPR spectra of the photoproducts were closely related to the size and/or the polarity of the distal pocket residues. The distal pocket of the E7 mutants seemed to be sterically crowded, even decreasing the side chain volume or changing its hydrophobicity by replacing amino acid at position 64. We have found that the mobility of the photodissociated NO molecule in the distal heme pocket was strongly governed by the nature of the amino acid residue at E11 position.
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Affiliation(s)
- H Hori
- Division of Biophysical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Japan.
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6
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Scott EE, Paster EV, Olson JS. The Stabilities of Mammalian Apomyoglobins Vary over a 600-Fold Range and Can Be Enhanced by Comparative Mutagenesis. J Biol Chem 2000. [DOI: 10.1016/s0021-9258(19)61489-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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7
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Chu GC, Tomita T, Sönnichsen FD, Yoshida T, Ikeda-Saito M. The heme complex of Hmu O, a bacterial heme degradation enzyme from Corynebacterium diphtheriae. Structure of the catalytic site. J Biol Chem 1999; 274:24490-6. [PMID: 10455111 DOI: 10.1074/jbc.274.35.24490] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hmu O, a heme degradation enzyme in Corynebacterium diphtheriae, forms a stoichiometric complex with iron protoporphyrin IX and catalyzes the oxygen-dependent conversion of hemin to biliverdin, carbon monoxide, and free iron. Using a multitude of spectroscopic techniques, we have determined the axial ligand coordination of the heme-Hmu O complex. The ferric complex shows a pH-dependent reversible transition between a water-bound hexacoordinate high spin neutral pH form and an alkaline form, having high spin and low spin states, with a pK(a) of 9. (1)H NMR, EPR, and resonance Raman of the heme-Hmu O complex establish that a neutral imidazole of a histidine residue is the proximal ligand of the complex, similar to mammalian heme oxygenase. EPR of the deoxy cobalt porphyrin IX-Hmu O complex confirms this proximal histidine coordination. Oxy cobalt-Hmu O EPR reveals a hydrogen-bonding interaction between the O(2) and an exchangeable proton in the Hmu O distal pocket and two distinct orientations for the bound O(2). Mammalian heme oxygenase has only one O(2) orientation. This difference and the mixed spin states at alkaline pH indicate structural differences in the distal environment between Hmu O and its mammalian counterpart.
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Affiliation(s)
- G C Chu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4970, USA
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8
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Sugimoto T, Unno M, Shiro Y, Dou Y, Ikeda-Saito M. Myoglobin mutants giving the largest geminate yield in CO rebinding in the nanosecond time domain. Biophys J 1998; 75:2188-94. [PMID: 9788913 PMCID: PMC1299892 DOI: 10.1016/s0006-3495(98)77662-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have measured the rebinding of carbon monoxide (CO) to some distal mutants of myoglobin (Mb) in the time range from 10(-8) to 10(-1) s by flash photolysis, in which the photodissociated CO rebinds to the heme iron without escaping to the solvent water from the protein matrix. We have found that the double mutants [His64-->Val/Val68-->Thr (H64V/V68T) and His64-->Val/Val68-->Ser (H64V/V68S)] have an extremely large geminate yield (70-80%) in water at 5 degreesC, in contrast to the 7% of the geminate yield of wild-type Mb. The CO geminate yields for these two mutants are the largest in those of Mb mutants reported so far, showing that the two mutants have a unique heme environment that favors CO geminate rebinding. Comparing the crystal structures and 1H-NMR and vibrational spectral data of H64V/V68T and H64V/V68S with those of other mutants, we discuss factors that may control the nanosecond geminate CO rebinding and CO migration in the protein matrix.
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Affiliation(s)
- T Sugimoto
- Faculty of Science, Gakushuin University, Mejiro, Toshima-ku, Tokyo 170, Japan
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9
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Lee HC, Scheuring E, Peisach J, Chance MR. Electron Spin Echo Envelope Modulation and Extended X-ray Absorption Fine Structure Studies of Active Site Models of Oxygenated Cobalt-Substituted Hemoproteins: Correlating Electron-Nuclear Couplings and Metal−Ligand Bond Lengths. J Am Chem Soc 1997. [DOI: 10.1021/ja9717166] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- H. Caroline Lee
- Contribution from the Department of Physiology and Biophysics, Center for Synchrotron Biosciences, and Biotechnology Resource in Pulsed EPR Spectroscopy, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461
| | - Eva Scheuring
- Contribution from the Department of Physiology and Biophysics, Center for Synchrotron Biosciences, and Biotechnology Resource in Pulsed EPR Spectroscopy, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461
| | - Jack Peisach
- Contribution from the Department of Physiology and Biophysics, Center for Synchrotron Biosciences, and Biotechnology Resource in Pulsed EPR Spectroscopy, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461
| | - Mark R. Chance
- Contribution from the Department of Physiology and Biophysics, Center for Synchrotron Biosciences, and Biotechnology Resource in Pulsed EPR Spectroscopy, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461
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10
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Brucker EA, Olson JS, Phillips GN, Dou Y, Ikeda-Saito M. High resolution crystal structures of the deoxy, oxy, and aquomet forms of cobalt myoglobin. J Biol Chem 1996; 271:25419-22. [PMID: 8810310 DOI: 10.1074/jbc.271.41.25419] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The structures of the deoxy, oxy, and aquomet forms of native sperm whale myoglobin reconstituted with cobalt protoporphyrin IX have been determined by x-ray crystallography. As expected, cobalt myoglobin closely resembles native iron myoglobin in overall structure, especially in their respective aquomet forms. In the cobalt oxymyoglobin structure, the Nepsilon of distal histidine 64 lies within hydrogen bonding distance to both the oxygen atom directly bonded to the cobalt and the terminal oxygen atom, in agreement with previous EPR and resonance Raman studies. The metal atom in cobaltous myoglobin does show a small 0.06-A out-of-porphyrin plane displacement when moving from the oxy to deoxy state. In the case of the native iron-containing myoglobin, the oxy to deoxy transition results in a larger 0.16-A displacement of the metal farther out of the porphyrin plane, attributed to an increase in spin from S = 0 to S = 2. The small displacement in cobalt myoglobin is due to a change in coordination geometry, not spin state (S = 1/2 for both cobalt deoxy- and oxymyoglobin). The small out-of-porphyrin plane movement of cobalt which accompanies deoxygenation of myoglobin also occurs in cobalt hemoglobin and serves to explain why cooperativity, although reduced, is still preserved when iron is replaced by cobalt in human hemoglobin.
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Affiliation(s)
- E A Brucker
- Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77005-1892, USA
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11
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Miller LM, Patel M, Chance MR. Identification of Conformational Substates in Oxymyoglobin through the pH-Dependence of the Low-Temperature Photoproduct Yield. J Am Chem Soc 1996. [DOI: 10.1021/ja952534j] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lisa M. Miller
- Contribution from the Department of Physiology and Biophysics, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461
| | - Mehul Patel
- Contribution from the Department of Physiology and Biophysics, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461
| | - Mark R. Chance
- Contribution from the Department of Physiology and Biophysics, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461
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12
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Navarro AM, Maldonado M, González-Lagoa J, López-Mejía R, López-Garriga J, Colón JL. Control of carbon monoxide binding states and dynamics in hemoglobin I of Lucina pectinata by nearby aromatic residues. Inorganica Chim Acta 1996. [DOI: 10.1016/0020-1693(95)04903-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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13
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Zhao X, Vyas K, Nguyen BD, Rajarathnam K, La Mar GN, Li T, Phillips GN, Eich RF, Olson JS, Ling J. A double mutant of sperm whale myoglobin mimics the structure and function of elephant myoglobin. J Biol Chem 1995; 270:20763-74. [PMID: 7657659 DOI: 10.1074/jbc.270.35.20763] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The functional, spectral, and structural properties of elephant myoglobin and the L29F/H64Q mutant of sperm whale myoglobin have been compared in detail by conventional kinetic techniques, infrared and resonance Raman spectroscopy, 1H NMR, and x-ray crystallography. There is a striking correspondence between the properties of the naturally occurring elephant protein and those of the sperm whale double mutant, both of which are quite distinct from those of native sperm whale myoglobin and the single H64Q mutant. These results and the recent crystal structure determination by Bisig et al. (Bisig, D. A., Di Iorio, E. E., Diederichs, K., Winterhalter, K. H., and Piontek, K. (1995) J. Biol. Chem. 270, 20754-20762) confirm that a Phe residue is present at position 29 (B10) in elephant myoglobin, and not a Leu residue as is reported in the published amino acid sequence. The single Gln64(E7) substitution lowers oxygen affinity approximately 5-fold and increases the rate of autooxidation 3-fold. These unfavorable effects are reversed by the Phe29(B10) replacement in both elephant myoglobin and the sperm whale double mutant. The latter, genetically engineered protein was originally constructed to be a blood substitute prototype with moderately low O2 affinity, large rate constants, and increased resistance to autooxidation. Thus, the same distal pocket combination that we designed rationally on the basis of proposed mechanisms for ligand binding and autooxidation is also found in nature.
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Affiliation(s)
- X Zhao
- Department of Chemistry, University of California, Davis 95616, USA
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14
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Dou Y, Admiraal SJ, Ikeda-Saito M, Krzywda S, Wilkinson AJ, Li T, Olson JS, Prince RC, Pickering IJ, George GN. Alteration of axial coordination by protein engineering in myoglobin. Bisimidazole ligation in the His64-->Val/Val68-->His double mutant. J Biol Chem 1995; 270:15993-6001. [PMID: 7608158 DOI: 10.1074/jbc.270.27.15993] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Pig and human myoglobin have been engineered to reverse the positions of the distal histidine and valine (i.e. His64(E7)-->Val and Val68(E11)-->His). Spectroscopic and ligand binding properties have been measured for human and pig H64V/V68H myoglobin, and the structure of the pig H64V/V68H double mutant has been determined to 2.07-A resolution by x-ray crystallography. The crystal structure shows that the N epsilon of His68 is located 2.3 A away from the heme iron, resulting in the formation of a hexacoordinate species. The imidazole plane of His68 is tilted relative to the heme normal; moreover it is not parallel to that of His93, in agreement with our previous proposal (Qin, J., La Mar, G. N., Dou, Y., Admiraal, S. J., and Ikeda-Saito, M. (1994) J. Biol. Chem. 269, 1083-1090). At cryogenic temperatures, the heme iron is in a low spin state, which exhibits a highly anisotropic EPR spectrum (g1 = 3.34, g2 = 2.0, and g3 < 1), quite different from that of the imidazole complex of metmyoglobin. The mean iron-nitrogen distance is 2.01 A for the low spin ferric state as determined by x-ray spectroscopy. The ferrous form of H64V/V68H myoglobin shows an optical spectrum that is similar to that of b-type cytochromes and consistent with the hexacoordinate bisimidazole hemin structure determined by the x-ray crystallography. The double mutation lowers the ferric/ferrous couple midpoint potential from +54 mV of the wild-type protein to -128 mV. Ferrous H64V/V68H myoglobin binds CO and NO to form stable complexes, but its reaction with O2 results in a rapid autooxidation to the ferric species. All of these results demonstrate that the three-dimensional positions of His64 and Val68 in the wild-type myoglobin are as important as the chemical nature of the side chains in facilitating reversible O2 binding and inhibiting autooxidation.
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Affiliation(s)
- Y Dou
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4970, USA
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15
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1H NMR investigation of distal mutant deoxy myoglobins. Interpretation of proximal His contact shifts in terms of a localized distal water molecule. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)43927-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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16
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Hargrove MS, Krzywda S, Wilkinson AJ, Dou Y, Ikeda-Saito M, Olson JS. Stability of myoglobin: a model for the folding of heme proteins. Biochemistry 1994; 33:11767-75. [PMID: 7918393 DOI: 10.1021/bi00205a012] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Factors governing the stability of sperm whale, pig, and human metmyoglobin were examined by (1) measuring guanidinium chloride induced unfolding of apoglobins containing 22 replacements at positions 29(B10), 43(CD1), 64(E7), 68(E11), and 107(G8), (2) determining the rates of hemin loss from the recombinant holoproteins, and (3) estimating constitutive expression levels of the corresponding genes in Escherichia coli TB-1 cells. The denaturant titrations were analyzed in terms of a two-step unfolding reaction, N(native apoprotein)-->I(intermediate)-->U(unfolded), in which the intermediate is visualized by an increase in tryptophan fluorescence emission. Two key conclusions were reached. First, high rates of hemin loss are not necessarily correlated with unstable globin structures and vice versa. In general, both rates of hemin loss and the equilibrium constants for apoprotein unfolding must be determined in order to understand the overall stability of heme proteins and to predict the efficiency of their expression. Second, polar residues in the distal pocket cause marked decreases in the overall stability of apomyoglobin. Removal of hemin from V68N and L29N sperm whale myoglobins produces the molten globular I state at pH 7, 25 degrees C, without addition of denaturant. In contrast, the H64L and H64F mutations produce apoproteins which are 10-30 times more stable than wild-type apoglobin. The latter results show that protein stability is sacrificed in order to have the distal histidine (H64) present to increase O2 affinity and inhibit autooxidation.
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Affiliation(s)
- M S Hargrove
- Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251-1892
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17
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Lee HC, Peisach J, Dou Y, Ikeda-Saito M. Electron-nuclear coupling to the proximal histidine in oxy cobalt-substituted distal histidine mutants of human myoglobin. Biochemistry 1994; 33:7609-18. [PMID: 8011627 DOI: 10.1021/bi00190a014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Electron spin echo envelope modulation (ESEEM) spectroscopy was used to investigate electron-nuclear coupling to the N epsilon of the proximal histidine (F8, His93) imidazole in oxyCo(II)-substituted distal histidine (E7, His64) mutants (His-->Leu, His-->Val, His-->Gly, His-->Gln) and recombinant wild-type human myoglobins (Mbs). Nuclear hyperfine and nuclear quadrupole coupling constants decrease in the order: H64L > H64V > or = H64G approximately H64Q > wild-type. The differences in couplings found for the four mutant proteins are correlated with the differences in polarity of the E7 side chain. On the basis of the relative orientation of the nuclear quadrupole and g tensors, obtained by computer simulation of ESEEM spectra, the Co-O-O bond angle of H64G and H64Q appears to be similar to that of oxyCo sperm whale Mb (and possibly wild-type human Mb) at room temperature [Hori et al. (1982) J. Biol. Chem. 257, 3636], while that in H64V and H64L is more obtuse. ESEEM measurements in D2O demonstrate the presence of a hydrogen bond between the distal histidine and bound O2 in the wild-type protein, as was found in oxyCo sperm whale and horse Mbs [Lee et al. (1992) Biochemistry 31, 7274]. This hydrogen bond leads to a reduction in the N epsilon coupling in the wild-type protein as compared to that in the E7 mutants. No hyperfine-coupled deuterons were found in any of the mutants, and therefore, the proposed hydrogen bond between bound O2 and the distal glutamine in H64Q [Ikeda-Saito et al. (1991) J. Biol. Chem. 266, 23641] could not be substantiated.
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Affiliation(s)
- H C Lee
- Department of Molecular Pharmacology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York 10461
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18
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1H NMR study of the solution molecular and electronic structure of engineered distal myoglobin His64(E7) Val/Val68(E11) His double mutant. Coordination of His64(E11) at the sixth position in both low-spin and high-spin states. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)42224-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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19
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Masuya F, Hori H. EPR studies on the photoproducts of manganese(II) protoporphyrin-IX substituted myoglobin nitrosyl complexes trapped at low temperature: effects of site-specific chemical modification of the distal histidine on ligand-binding structures. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1203:99-103. [PMID: 8218396 DOI: 10.1016/0167-4838(93)90041-o] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Manganese(II) protoporphyrin-IX substituted myoglobin with site-specifically cyanated or N-tetrazolated distal histidine (His) was prepared and low-temperature photolysis of nitric oxide (NO) from their nitrosyl complexes was examined by electron paramagnetic resonance (EPR) spectroscopy in order to elucidate the steric crowding of the distal heme moiety. The photoproduct of NO complex of the tetrazolated Mn(II)Mb (tetrazole-Mn(II)Mb) exhibited widespread absorption in the magnetic field from zero to 0.4 T due to a spin-coupled interaction between the high-spin Mn(II) center (S = 5/2) and the photodissociated NO (S = 1/2) trapped adjacent to the metal center. This indicates that the NO complex of tetrazole-Mn(II)Mb has sterically restricted distal heme pocket. On the other hand, the photoproduct of NO complex of cyanated Mn(II)Mb (BrCN-Mn(II)Mb) exhibited only the broad g = 6 absorption due to the magnetic dipole-dipole interaction between the photodissociated NO and the high-spin Mn(II) center. A drastic conformational change in the heme-ligand moiety, in which the distal histidine side chain is pushed toward the outside of the heme pocket, leaving an open space in the distal heme pocket, can be suggested.
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Affiliation(s)
- F Masuya
- Department of Biophysical Engineering, Faculty of Engineering Science, Osaka University, Japan
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20
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Lopez MA, Kollman PA. Application of molecular dynamics and free energy perturbation methods to metalloporphyrin-ligand systems II: CO and dioxygen binding to myoglobin. Protein Sci 1993; 2:1975-86. [PMID: 8268807 PMCID: PMC2142277 DOI: 10.1002/pro.5560021119] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The protein contribution to the relative binding affinity of the ligands CO and O2 toward myoglobin (Mb) has been simulated using free energy perturbation calculations. The tautomers of the His E7 residue are different for the oxymyoglobin (MbO2) and carboxymyoglobin (MbCO) systems. This was modeled by performing two-step calculations that mutate the ligand and mutate the His E7 tautomers in separate steps. Differences in hydrogen bonding to the O2 and CO ligands were incorporated into the model. The O2 complex was calculated to be 2-3 kcal/mol more stable than the corresponding CO complex when compared to the same difference in an isolated heme control. This value agrees well with the experimental value of 2.0 kcal/mol. In qualitative agreement with experiments, the Fe-C-O bond is found to be bent (theta = 159.8 degrees) with a small tilt (theta = 6.2 degrees). The contributions made by each of the 29 residues--within the 9.0-A radius of the iron atom--to the free energy difference are separated into van der Waals and electrostatic contributions; the latter contributions are dominant. Aside from the proximal histidine and the heme group, the residues having the largest difference in free energy in mutating MbO2-->MbCO are His E7, Phe CD1, Phe CD4, Val E11, and Thr E10.
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Affiliation(s)
- M A Lopez
- Department of Chemistry and Biochemistry, California State University at Long Beach 90840-3903
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21
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Specific modification of structure and property of myoglobin by the formation of tetrazolylhistidine 64(E7). Reaction of the modified myoglobin with molecular oxygen. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(20)80683-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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22
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Ikeda-Saito M, Dou Y, Yonetani T, Olson J, Li T, Regan R, Gibson Q. Ligand diffusion in the distal heme pocket of myoglobin. A primary determinant of geminate rebinding. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53115-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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23
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Yamamoto Y, Iwafune K, Chûjô R, Inoue Y, Imai K, Suzuki T. Molecular mechanism for ligand stabilization in the mollusc myoglobin possessing the distal Val residue. J Mol Biol 1992; 228:343-6. [PMID: 1453445 DOI: 10.1016/0022-2836(92)90823-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Myoglobin extracted from the triturative stomach of Dolabella auricularia, a common mollusc found on the Japanese coast, possesses naturally occurring substitution at the distal E7 position (Val-E7) and its oxygen affinity is only slightly lower than those of the common mammalian myoglobins possessing the usual His-E7. 1H nuclear magnetic resonance studies of Dolabella met-cyano myoglobin have revealed that a guanidino NH proton of Arg-E10 is hydrogen-bonded to the Fe-bound CN-. The role of Arg-E10 as a hydrogen-bond donor for Fe-bound ligand in the present myoglobin appears to be responsible for its relatively high ligand affinity.
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Affiliation(s)
- Y Yamamoto
- Department of Biomolecular Engineering, Tokyo Institute of Technology, Japan
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24
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Coordination structure of the ferric heme iron in engineered distal histidine myoglobin mutants. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)50024-7] [Citation(s) in RCA: 123] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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25
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Gibson Q, Regan R, Elber R, Olson J, Carver T. Distal pocket residues affect picosecond ligand recombination in myoglobin. An experimental and molecular dynamics study of position 29 mutants. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41630-4] [Citation(s) in RCA: 124] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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26
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Electronic and stereochemical characterizations of intermediates in the photolysis of ferric cytochrome P450scc nitrosyl complexes. Effects of cholesterol and its analogues on ligand binding structures. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)36972-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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