1
|
Findsen EW, Shelnutt JA, Ondrias MR. Photodynamics of nickel-porphyrins in noncoordinating solvents: characterization of d-d excited states using transient Raman spectroscopy. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100313a014] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
2
|
Crawford BA, Ondrias MR, Shelnutt JA. Transient Raman difference spectroscopy of nickel(II)-uroporphyrin .pi.-.pi. complexes. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100380a024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
3
|
|
4
|
|
5
|
Alden RG, Ondrias MR, Shelnutt JA. Influences of .pi.-.pi. complex formation, dimerization, and binding to hemoglobin on the planarity of nickel(II) porphyrins. J Am Chem Soc 2002. [DOI: 10.1021/ja00158a030] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
6
|
Alden RG, Ondrias MR, Courtney S, Findsen EW, Friedman JM. Power-induced broadening of transient resonance Raman spectra of deoxyhemoglobin. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100364a013] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
7
|
Simpson MC, Millett F, Fan B, Ondrias MR. Transient Resonance Raman Evidence for Structural Reorganizational Dynamics during Electron Transfer in Ruthenated Yeast Cytochrome c. J Am Chem Soc 2002. [DOI: 10.1021/ja00116a044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
8
|
|
9
|
|
10
|
Findsen EW, Centeno J, Babcock GT, Ondrias MR. Cytochrome a3 hemepocket relaxation subsequent to ligand photolysis from cytochrome oxidase. J Am Chem Soc 2002. [DOI: 10.1021/ja00252a011] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
11
|
|
12
|
Alden RG, Chavez MD, Ondrias MR, Courtney SH, Friedman JM. Direct measurement of vibrational temperatures in photoexcited deoxyhemoglobin on picosecond time scales. J Am Chem Soc 2002. [DOI: 10.1021/ja00164a071] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
13
|
Findsen EW, Alston K, Shelnutt JA, Ondrias MR. Transient photoligation behavior of nickel protoporphyrin reconstituted myoglobin and hemoglobin. J Am Chem Soc 2002. [DOI: 10.1021/ja00274a026] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
14
|
Sparks LD, Medforth CJ, Park MS, Chamberlain JR, Ondrias MR, Senge MO, Smith KM, Shelnutt JA. Metal dependence of the nonplanar distortion of octaalkyltetraphenylporphyrins. J Am Chem Soc 2002. [DOI: 10.1021/ja00055a030] [Citation(s) in RCA: 213] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
15
|
Franzen S, Miskowski VM, Shreve AP, Wallace-Williams SE, Woodruff WH, Ondrias MR, Barr ME, Moore L, Boxer SG. Electrostatic and conformational effects on the electronic structures of distortional isomers of a mixed-valence binuclear Cu complex. Inorg Chem 2001; 40:6375-82. [PMID: 11720490 DOI: 10.1021/ic010494g] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The electronic structure of the binuclear copper complex [Cu(2)(L)](3+) [L = N(CH(2)CH(2)N(H)CH(2)CH(2)N(H)CH(2)CH(2))(3)N] has been investigated by resonance Raman and electroabsorption spectroscopy. Crystallographic Cu(2) distances of 2.364(1) and 2.415(1) A determined for the nitrate and acetate salts, respectively, are consistent with a substantial metal-metal interaction. The Cu-Cu bonding interaction in the binuclear complex is modulated both in the solid state and in solution by the ligand environment through coupling to ligand torsional modes that are, in turn, stabilized by hydrogen bonding. Electroabsorption data on the three major visible and near-infrared electronic transitions of Cu(2)L, lambda(max) (epsilon(max)) = 1000 nm ( approximately 1200 M(-1) cm(-1)), 748 nm (5600 M(-1) cm(-1)), and 622 nm (3350 M(-1) cm(-1)), reveal a difference dipole moment between the ground and excited states (Deltamu(A)) because of symmetry breaking. The difference polarizability for all three of the transitions is negative, indicating that the ground state is more polarizable than the excited state. A general model to explain this behavior in terms of the proximity of accessible transitions involving copper d electrons is proposed to explain the larger polarizability of the ground state. Raman excitation profiles (REPs) provide evidence for multiple conformational states of [Cu(2)(L)](3+). Separate REPs were obtained for each of the components of the two major Raman bands for nu(1) (a Cu-Cu stretching mode) and nu(2) (a Cu-Cu-N(eq) bending mode). The Raman data along with quantum chemical ZINDO/S CI calculations provide evidence for isomeric forms of Cu(2)L with strong coupling between the conformation of L and the Cu-Cu bond length.
Collapse
Affiliation(s)
- S Franzen
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Gao F, Qin H, Knaff DB, Zhang L, Yu L, Yu CA, Gray KA, Daldal F, Ondrias MR. Q-Band resonance Raman investigation of turnip cytochrome f and Rhodobacter capsulatus cytochrome c1. Biochim Biophys Acta 1999; 1430:203-13. [PMID: 10082948 DOI: 10.1016/s0167-4838(98)00284-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The results of a comprehensive Q-band resonance Raman investigation of cytochrome c1 and cytochrome f subunits of bc1 and b6f complexes are presented. Q-band excitation provides a particularly effective probe of the local heme environments of these species. The effects of protein conformation (particularly axial ligation) on heme structure and function were further investigated by comparison of spectra obtained from native subunits to those of a site directed c1 mutant (M183L) and various pH-dependent species of horse heart cytochrome c. In general, all species examined displayed variability in their axial amino acid ligation that suggests a good deal of flexibility in their hemepocket conformations. Surprisingly, the large scale protein rearrangements that accompany axial ligand replacement have little or no effect on macrocycle geometry in these species. This indicates the identity and/or conformation of the peptide linkage between the two cysteines that are covalently linked to the heme periphery may determine heme geometry.
Collapse
Affiliation(s)
- F Gao
- Department of Chemistry, University of New Mexico, Albuquerque, NM 87131, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Abstract
Recently published crystallographic studies of mitochondrial bc1 complexes have stimulated renewed interest in the active site architecture of these important integral membrane proteins. We present resonance Raman spectra obtained via variable excitation within the heme Q-band from samples poised in several different net redox states. Appropriate subtraction and polarization analysis allows the vibrational behavior of the individual heme bL,bH, and c1 sites to be assessed. The spectra of the b hemes are particularly noteworthy. They exhibit evidence for a protonation equilibrium involving heme axial ligands and reveal a marked structural heterogeneity at the heme bH site that most likely involves nonplanar distortions of the macrocycle. The possible implications of these findings for heme functionality are discussed.
Collapse
Affiliation(s)
- F Gao
- Department of Chemistry, University of New Mexico, Albuquerque 87131 USA
| | | | | | | | | | | | | |
Collapse
|
18
|
Fan B, Simpson MC, Shelnutt JA, Martinez L, Falcon R, Buranda T, Pastuszyn AJ, Ondrias MR. Synthesis and Physical Characterization of Novel Heme-Based Model Systems for Photoinitiated Electron Transfer. 2. Direct Ruthenation of Microperoxidase-11. Inorg Chem 1997. [DOI: 10.1021/ic970040c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B. Fan
- Departments of Chemistry and Biochemistry, University of New Mexico, Albuquerque, New Mexico 87131, and Fuel Sciences Divison, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - M. C. Simpson
- Departments of Chemistry and Biochemistry, University of New Mexico, Albuquerque, New Mexico 87131, and Fuel Sciences Divison, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - J. A. Shelnutt
- Departments of Chemistry and Biochemistry, University of New Mexico, Albuquerque, New Mexico 87131, and Fuel Sciences Divison, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - L. Martinez
- Departments of Chemistry and Biochemistry, University of New Mexico, Albuquerque, New Mexico 87131, and Fuel Sciences Divison, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - R. Falcon
- Departments of Chemistry and Biochemistry, University of New Mexico, Albuquerque, New Mexico 87131, and Fuel Sciences Divison, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - T. Buranda
- Departments of Chemistry and Biochemistry, University of New Mexico, Albuquerque, New Mexico 87131, and Fuel Sciences Divison, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - A. J. Pastuszyn
- Departments of Chemistry and Biochemistry, University of New Mexico, Albuquerque, New Mexico 87131, and Fuel Sciences Divison, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - M. R. Ondrias
- Departments of Chemistry and Biochemistry, University of New Mexico, Albuquerque, New Mexico 87131, and Fuel Sciences Divison, Sandia National Laboratory, Albuquerque, New Mexico 87185
| |
Collapse
|
19
|
Fan B, Fontenot DL, Larsen RW, Simpson MC, Shelnutt JA, Falcon R, Martinez L, Niu S, Zhang S, Niemczyk T, Ondrias MR. Synthesis and Physical Characterization of Novel Heme-Based Model Systems for Photoinitiated Electron Transfer. 1. Complexation of a RuProHis Bifunctional Peptide and Microperoxidase-11. Inorg Chem 1997. [DOI: 10.1021/ic9700415] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- B. Fan
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and Fuel Sciences Division, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - D. L. Fontenot
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and Fuel Sciences Division, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - R. W. Larsen
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and Fuel Sciences Division, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - M. C. Simpson
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and Fuel Sciences Division, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - J. A. Shelnutt
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and Fuel Sciences Division, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - R. Falcon
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and Fuel Sciences Division, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - L. Martinez
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and Fuel Sciences Division, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - S. Niu
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and Fuel Sciences Division, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - S. Zhang
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and Fuel Sciences Division, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - T. Niemczyk
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and Fuel Sciences Division, Sandia National Laboratory, Albuquerque, New Mexico 87185
| | - M. R. Ondrias
- Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, Life Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and Fuel Sciences Division, Sandia National Laboratory, Albuquerque, New Mexico 87185
| |
Collapse
|
20
|
Simpson MC, Peterson ES, Shannon CF, Eads DD, Friedman JM, Cheatum CM, Ondrias MR. Transient Raman Observations of Heme Electronic and Vibrational Photodynamics in Deoxyhemoglobin. J Am Chem Soc 1997. [DOI: 10.1021/ja961198j] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. C. Simpson
- Contribution from the Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87135, and Department of Biophysics and Physiology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - E. S. Peterson
- Contribution from the Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87135, and Department of Biophysics and Physiology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - C. F. Shannon
- Contribution from the Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87135, and Department of Biophysics and Physiology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - D. D. Eads
- Contribution from the Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87135, and Department of Biophysics and Physiology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - J. M. Friedman
- Contribution from the Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87135, and Department of Biophysics and Physiology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - C. M. Cheatum
- Contribution from the Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87135, and Department of Biophysics and Physiology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - M. R. Ondrias
- Contribution from the Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87135, and Department of Biophysics and Physiology, Albert Einstein College of Medicine, Bronx, New York 10461
| |
Collapse
|
21
|
Gao F, Qin H, Simpson MC, Shelnutt JA, Knaff DB, Ondrias MR. Isolation and characterization of vibrational spectra of individual heme active sites in cytochrome bc1 complexes from Rhodobacter capsulatus. Biochemistry 1996; 35:12812-9. [PMID: 8841124 DOI: 10.1021/bi960419v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Resonance Raman spectra of bc1 complexes and isolated c1 subunit from Rhodobacter capsulatus have been obtained using a variety of excitation wavelengths. Spectra obtained via Q-band excitation of bc1 complexes in different redox states were separated to yield the individual vibrational spectra of each of the three heme active sites. Hemes bH and c1 exhibit vibrational spectra typical of b- and c-type hemes, respectively. In contrast, the spectrum of heme bL is anomalous with respect to those of other hemes b. The isolated spectra were also used to assess the effects of inhibitor binding on the local structural environments of the hemes. Neither antimycin nor myxothiazol binding produces dramatic structural perturbations at the hemes. Heme c1 is completely unaffected by the presence of either inhibitor. The vibrational spectra of hemes bH and bL are slightly altered by antimycin and myxothiazol binding, respectively.
Collapse
Affiliation(s)
- F Gao
- Department of Chemistry, University of New Mexico, Albuquerque 87131, USA
| | | | | | | | | | | |
Collapse
|
22
|
Simpson MC, Millett F, Pan LP, Larsen RW, Hobbs JD, Fan B, Ondrias MR. Transient and time-resolved resonance Raman investigation of photoinitiated electron transfer in ruthenated cytochromes c. Biochemistry 1996; 35:10019-30. [PMID: 8756464 DOI: 10.1021/bi960253y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Ruthenation of exterior amino acid residues of heme proteins provides an effective means by which biological ET reactions can be studied within the context of highly complex protein environments. Resonance Raman spectroscopy can probe both ET kinetics and structural dynamics at the molecular level. Here we present the first comprehensive use of time-resolved and transient resonance Raman spectroscopies to examine photoinduced ET in cytochromes. Two ruthenated cytochromes c, Ru(lys72)-cyt.c and Ru(cyt102)cyt.c, were studied with TRRS using 10 ns laser pulses and with TRRRS on a 10 ns to 10 ms time scale. It was found that resonance Raman protocols can effectively trace ET kinetics and associated heme--protein structural dynamics. Care must be exercised, however, when drawing comparisons to measurements made by other methods (i.e., transient absorbance). The TRRS studies directly probe the heme and its local environment and reveal that the heme dynamics accompanying ET are very rapid relative to phenomenological ET kinetics. The heme and its local environment evolve to their equilibrium (ferrous) structure in less than 10 ns subsequent to ET, with no evidence for the existence of metastable heme pocket geometries analogous to those observed in the dynamic response of hemoglobins and oxidases. Finally, species-specific differences are observed in the photoinduced ET kinetics and heme structural dynamics. However, these differences are confined to nanosecond or faster time scales.
Collapse
Affiliation(s)
- M C Simpson
- Department of Chemistry, University of New Mexico, Albuquerque, USA
| | | | | | | | | | | | | |
Collapse
|
23
|
Wang J, Larsen RW, Moench SJ, Satterlee JD, Rousseau DL, Ondrias MR. Cytochrome c peroxidase complexed with cytochrome c has an unperturbed heme moiety. Biochemistry 1996; 35:453-63. [PMID: 8555215 DOI: 10.1021/bi9518499] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Transient resonance Raman, Raman difference, circular dichroism (CD), and optical absorption studies have been carried out on the electrostatic complexes formed by yeast cytochrome c peroxidase (CCP) with horse cytochrome c (Cytc) in low ionic strength solutions. In all the complexes examined [e.g., CCP(II)/Cytc(II), CCP(III)/Cytc(II), CCP(III)/Cytc(III)], the local heme environments of both proteins are largely unperturbed upon complexation. Specifically, CCP preserves a completely pentacoordinate high-spin heme in both its ferric and ferrous forms in CCP/Cytc complexes and uncomplexed mixtures. We found no evidence corroborating the previously reported increase in the low-spin fraction of CCP heme upon complexation with Cytc [Hildebrandt et al. (1992) Biochemistry 31, 2384-2392]. Instead, our Raman data strongly suggest that the H-bonding networks in the distal and proximal pockets of CCP are well maintained in the complexes. On the other hand, CD spectra of CCP(III)/Cytc(III) complexes showed substantial variations (relative to the uncomplexed mixtures) in the far-UV region, reflecting some protein conformational rearrangements. In addition, the spectral data suggest that complexation with Cytc affects the previously observed pH-dependent flexibility of the heme structure of CCP and thus influences the photodynamics of the CCP active site.
Collapse
Affiliation(s)
- J Wang
- Department of Chemistry, University of New Mexico, Albuquerque 87131, USA
| | | | | | | | | | | |
Collapse
|
24
|
Garcia Castillo MC, Lou BS, Ondrias MR, Robertson DE, Knaff DB. Characterization of flavocytochrome C552 from the thermophilic photosynthetic bacterium Chromatium tepidum. Arch Biochem Biophys 1994; 315:262-6. [PMID: 7986066 DOI: 10.1006/abbi.1994.1498] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A M(r) 68 kDa flavocytochrome c552 has been isolated from the thermophilic photosynthetic purple sulfur bacterium Chromatium tepidum and shown to consist of a M(r) 25 kDa subunit that contains two covalently bound heme c and a M(r) 43 kDa subunit that probably contains a single FAD. The prosthetic group content, absorbance spectra, and subunit composition of the C. tepidum flavocytochrome are quite similar to those previously reported for the flavocytochrome c552 isolated from a mesophilic Chromatium species, Chromatium vinosum. The oxidation-reduction properties of the hemes present in the C. tepidum flavocytochrome have been characterized by titrations, the effect of temperature on the catalytic activity of the protein has been investigated, and the heme environment has been characterized using resonance Raman spectroscopy.
Collapse
Affiliation(s)
- M C Garcia Castillo
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409-1061
| | | | | | | | | |
Collapse
|
25
|
Abstract
Resonance Raman spectroscopy (RRS) has been employed to characterize cytochromes c1 isolated from bc1 complexes of beef heart mitochondria and Rhodopseudomonas sphaeroides. The data obtained in this study extend the physical characterization of cytochromes c1 and focus on the effects of the local protein environment on the heme active site. While the general characteristics of the cytochromes c1 are similar to those of smaller soluble cytochromes c, the behavior of several core-size and ligation-sensitive heme modes reveal that significant systematic differences exist between those species. These, most likely, result from changes in the heme axial-ligand interactions.
Collapse
Affiliation(s)
- B S Lou
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | | | | | | | |
Collapse
|
26
|
Hirasawa M, Chang KT, Dose MM, Lou BS, Ondrias MR, Knaff DB. Characterization of two low-potential cytochromes from bean sprouts. Biochim Biophys Acta 1993; 1141:253-61. [PMID: 8443211 DOI: 10.1016/0005-2728(93)90050-p] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Two cytochromes have been isolated from chlorophyll-free bean sprouts, purified and characterized. The more abundant cytochrome was purified to apparent homogeneity and exhibits visible region absorbance maxima at 416, 520 and 550 nm in the reduced form and at 410 and 530 nm in the oxidized form. Although Resonance Raman spectra of this cytochrome closely resemble those of c-type cytochromes, pyridine hemochromogen analysis suggests that this cytochrome may contain a variant of heme c as its prosthetic group. The cytochrome has an apparent molecular mass of 12.5 kDa, an isoelectric point > 9.0 and a midpoint oxidation-reduction potential (Em) of -130 mV at pH 8.0. The less abundant of the two cytochromes, which was not completely purified, exhibits absorbance maxima at 438 and 560 nm in the reduced form and at 411 nm in the oxidized form and was shown to contain heme c as a prosthetic group. This cytochrome, which may also contain FAD, has an apparent molecular mass of approx. 38 kDa, an isoelectric point > 9.0 and Em = -300 mV. Preliminary results indicate that both cytochromes can form electrostatically-stabilized complexes with ferredoxin, suggesting the possibility that one or both of the cytochromes may participate in low-potential, non-photosynthetic electron transfer pathways involving ferredoxin.
Collapse
Affiliation(s)
- M Hirasawa
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409-1061
| | | | | | | | | | | |
Collapse
|
27
|
Schneebeck MC, Vigil LE, Friedman JM, Chavez MD, Ondrias MR. Heme-CO religation in photolyzed hemoglobin: a time-resolved Raman study of the Fe-CO stretching mode. Biochemistry 1993; 32:1318-23. [PMID: 8448140 DOI: 10.1021/bi00056a017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Time-resolved resonance Raman spectroscopy has been employed to monitor geminate heme-CO rebinding in photolyzed HbCO. The excitation frequency was tuned to enhance the scattering from rebound heme sites 20-500 ns subsequent to CO photolysis. The behavior of vFe-C during ligand rebinding has important ramifications concerning heme pocket dynamics of the distinct equilibrium configurations of the six-coordinate heme sites. During the geminate phase of recombination, the Fe-CO bond strengths and configurations of the rebound sites (inferred from the positions and line widths of vFe-C) were found to be the same as those of equilibrium configurations of HbCO within 500 ns of CO photolysis for all samples. No evidence was found for the existence of transient metastable configurations during geminate recombination. Spectra obtained at earlier times (100 ns) revealed small differences in the geminate rebinding rates of the two equilibrium configurations. Since there is little or no further CO rebinding between 100 and 500 ns after photolysis, some interconversion must occur between the dominant HbCO configurations on a submicrosecond time scale.
Collapse
Affiliation(s)
- M C Schneebeck
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | | | | | |
Collapse
|
28
|
Wang J, Zhu H, Ondrias MR. Protein conformational perturbations affect the photoreduction of native cytochrome c peroxidase (III) at alkaline pH. Biochemistry 1992; 31:12847-54. [PMID: 1334434 DOI: 10.1021/bi00166a020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ferric cytochrome c peroxidase (CCP) undergoes a ligation-state transition from a pentacoordinate, high-spin (5c/hs) heme to a hexacoordinate, low-spin (6c/1s) heme when titrated over a pH range of 7.30-9.70. This behavior is similar to that exhibited by the ferrous form of the enzyme. However, the photodissociation of the low-spin, axial ligand, exhibited by ferrous CCP at alkaline pH, is not observed for ferric CCP. Instead, a photoinduced reduction of the ferric heme is apparent in the pH range 7.90-9.70. In the absence of O2 and redox mediators such as methyl viologen (MV2+), the reoxidation of the photoreduced enzyme is very slow (tau 1/2 approximately 3 min). F(-)-bound CCP(III) (6c/hs) displays similar pH-dependent photoreduction. Horseradish peroxidase, however, does not. The formation of 6c/1s heme coincides with the onset of appreciable photoreduction (between laser pulses, > 60 ms) of CCP (III) at alkaline pH, suggesting a global protein conformational rearrangement within or around its heme pocket. Photoreduction of alkaline CCP(III) most likely involves intramolecular electron transfer (ET) from the aromatic residue in the proximal heme pocket to the photoexcited heme. We speculate that the kinetics of electron transfer are affected by changes in the orientation of Trp-191.
Collapse
Affiliation(s)
- J Wang
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | |
Collapse
|
29
|
Larsen RW, Nunez DJ, MacLeod J, Shiemke AK, Musser SM, Nguyen HH, Ondrias MR, Chan SI. Spectroscopic characterization of heme A reconstituted myoglobin. J Inorg Biochem 1992; 48:21-31. [PMID: 1326598 DOI: 10.1016/0162-0134(92)80049-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The focus of this study was to examine the functional role of the unusual peripheral substitution of heme A. The effects of heme A stereochemistry on the reconstitution of the porphyrin have been examined in the heme A-apo-myoglobin complex using optical absorption and resonance Raman and electron paramagnetic resonance spectroscopies. The addition of one equivalent of heme A to apo-Mb produces a complex which displays spectroscopic signals consistent with a distribution of high- and low-spin heme chromophores. These results indicate that the incorporation of heme A into apo-Mb significantly perturbs the protein refolding.
Collapse
Affiliation(s)
- R W Larsen
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena 91125
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Larsen RW, Nunez DJ, Morgan WT, Muhoberac BB, Ondrias MR. Resonance Raman investigation of the effects of copper binding to iron-mesoporphyrin.histidine-rich glycoprotein complexes. Biophys J 1992; 61:1007-17. [PMID: 1581496 PMCID: PMC1260360 DOI: 10.1016/s0006-3495(92)81908-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Histidine-rich glycoprotein (HRG) binds both hemes and metal ions simultaneously with evidence for interaction between the two. This study uses resonance Raman and optical absorption spectroscopies to examine the heme environment of the 1:1 iron-mesoporphyrin.HRG complex in its oxidized, reduced and CO-bound forms in the absence and presence of copper. Significant perturbation of Fe(3+)-mesoporphyrin.HRG is induced by Cu2+ binding to the protein. Specifically, high frequency heme resonance Raman bands indicative of low-spin, six-coordinate iron before Cu2+ binding exhibit monotonic intensity shifts to bands representing high-spin, five-coordinate iron. The latter coordination is in contrast to that found in hemoglobin and myoglobin, and explains the Cu(2+)-induced decrease and broadening of the Fe(3+)-mesoporphyrin.HRG Soret band concomitant with the increase in the high-spin marker band at 620 nm. After dithionite reduction, the Fe(2+)-mesoporphyrin.HRG complex displays high frequency resonance Raman bands characteristic of low-spin heme and no iron-histidine stretch, which together suggest six-coordinate iron. Furthermore, the local heme environment of the complex is not altered by the binding of Cu1+. CO-bound Fe(2+)-mesoporphyrin.HRG exhibits bands in the high and low frequency regions similar to those of other CO-bound heme proteins except that the iron-CO stretch at 505 cm-1 is unusually broad with delta nu approximately 30 cm-1. The dynamics of CO photolysis and rebinding to Fe(2+)-mesoporphyrin.HRG are also distinctive. The net quantum yield for photolysis at 10 ns is low relative to most heme proteins, which may be attributed to very rapid geminate recombination. A similar low net quantum yield and broad iron-CO stretch have so far only been observed in a dimeric cytochrome c' from Chromatium vinosum. Furthermore, the photolytic transient of Fe(2+)-mesoporphyrin.HRG lacks bands corresponding to high-spin, five-coordinate iron as is found in hemoglobin and myoglobin under similar experimental conditions, suggesting iron hexacoordination before CO recombination. These data are consistent with a closely packed distal heme pocket that hinders ligand diffusion into the surrounding solvent.
Collapse
Affiliation(s)
- R W Larsen
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | | | | | |
Collapse
|
31
|
Abstract
The ferrous form of native cytochrome c peroxidase (CCP) is known to undergo a reversible transition when titrated over the pH range of 7.00-9.70. This transition produces a conversion from a pentacoordinate high-spin to a hexacoordinate low-spin heme active site and is clearly apparent in the heme optical absorption spectra. Here, we report the characterization of this transition and its effect upon the local heme environment using various optical spectroscopies. The formation of hexacoordinate low-spin heme is interpreted to involve the binding of His-52 at the distal site after the perturbation of the extensive H-bonded network within and around the heme pocket of CCP(II) at alkaline pH. Interestingly, CD investigations of CCP(II) in the far-UV and Soret regions indicate the dissappearance of a single high-spin species and the existence of at least two low-spin species of CCP(II) as the pH is raised above 7.90. Furthermore, transient resonance Raman experiments demonstrate that the hexacoordinate low-spin species can be photolyzed within 10-ns laser pulses, producing a species similar to the low-pH (high-spin) form of CCP(II) at alkaline pH. However, the extent of photolysis is quite pH dependent, with a maximum photodissociation yield at pH = 8.50.
Collapse
Affiliation(s)
- J L Wang
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | |
Collapse
|
32
|
Hobbs JD, Wynn M, Nunez DJ, Malkin R, Knaff DB, Ondrias MR. Structural characterization of heme sites in spinach cytochrome b6f complexes: a resonance Raman study. Biochim Biophys Acta 1991; 1059:37-44. [PMID: 1873297 DOI: 10.1016/s0005-2728(05)80185-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Resonance Raman spectra of cytochrome b6f complexes isolated from spinach chloroplasts have been obtained. Selective resonance enhancements and partial reductions of the complex by redox mediators were used to isolate and identify the contributions of heme b6 and heme f sites to the observed spectra. Corresponding spectra for turnip cytochrome f have also been obtained. Power-dependent photoreduction was observed in cytochrome f of the complex as well as in the isolated cytochrome f during the course of the Raman experiments.
Collapse
Affiliation(s)
- J D Hobbs
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | | | | | | | |
Collapse
|
33
|
Larsen RW, Chavez MD, Nunez DJ, Davidson MW, Knaff DB, Krulwich TA, Ondrias MR. Resonance Raman investigation of a soluble cytochrome c552 from alkaliphilic Bacillus firmus RAB. Arch Biochem Biophys 1990; 283:266-70. [PMID: 2177323 DOI: 10.1016/0003-9861(90)90641-b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The environment of the heme site of a low-potential soluble cytochrome (c552) from alkaliphilic Bacillus firmus RAB has been characterized with resonance Raman scattering and compared to that of horse heart cytochrome c. The Raman data indicate that vibrational bands sensitive to the axial ligation of the heme, as well as modes sensitive to the heme peripheral environment in cytochrome c552, are distinct from those of horse heart cytochrome c. The spectra of cytochrome c552 display resonance Raman modes indicative of a methionine as the sixth ligand in the oxidized form, while the reduced form appears to contain a nitrogenous-based sixth ligand. In addition, Q-band excitation reveals differences among vibrational modes in cytochrome c552 that are sensitive to the amino acid environment surrounding the heme.
Collapse
Affiliation(s)
- R W Larsen
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | | | | | | | | | |
Collapse
|
34
|
Larsen RW, Li W, Copeland RA, Witt SN, Lou BS, Chan SI, Ondrias MR. Room temperature characterization of the dioxygen intermediates of cytochrome c oxidase by resonance Raman spectroscopy. Biochemistry 1990; 29:10135-40. [PMID: 2176863 DOI: 10.1021/bi00495a018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Resonance Raman spectroscopy was employed to investigate the heme structures of catalytic intermediates of cytochrome c oxidase at room temperature. The high-frequency resonance Raman spectra were obtained for compound C (the two-electron-reduced dioxygen intermediate), ferryl (the three-electron-reduced dioxygen intermediate), and the fully oxidized enzyme. Compound C was formed by photolyzing CO mixed-valence enzyme in the presence of O2. The ferryl intermediate was formed by reoxidation of the fully reduced enzyme by an excess of H2O2. Two forms of the oxidized enzyme were prepared by reoxidizing the fully reduced enzyme with O2. Our data indicate that, in compound C, cyt a3 is either intermediate or low spin and is nonphotolabile and its oxidation state marker band, v4, appears a higher frequency than that of the resting form of the enzyme. The ferryl intermediate also displays a low-spin cyt a3, which is nonphotolabile, and an even higher frequency for the oxidation state marker band, v4. The reoxidized form of cytochrome c oxidase with a Soret absorption maximum at 420 nm has an oxidation state marker band (v4) in a position similar to that of the resting form, while the spin-state region resembles that of compound C. This species subsequently decays to a second oxidized from of the enzyme, which displays a high-frequency resonance Raman spectrum identical with that of the original resting enzyme.
Collapse
Affiliation(s)
- R W Larsen
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | | | | | | | | | |
Collapse
|
35
|
Hobbs DD, Kriauciunas A, Güner S, Knaff DB, Ondrias MR. Resonance Raman spectroscopy of cytochrome bc1 complexes from Rhodospirillum rubrum: initial characterization and reductive titrations. Biochim Biophys Acta 1990; 1018:47-54. [PMID: 2165419 DOI: 10.1016/0005-2728(90)90108-g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Resonance Raman spectra of bc1 complexes from Rhodospirillum rubrum have been obtained. Various resonance conditions and the stoichiometric redox titration of the complex were used to isolate and identify the contributions of the heme c1 and heme b active sites to the observed spectra. The complex was found to partially photoreduce when exposed to laser excitation.
Collapse
Affiliation(s)
- D D Hobbs
- Department of Chemistry, University of New Mexico, Albuquerque
| | | | | | | | | |
Collapse
|
36
|
Chance MR, Courtney SH, Chavez MD, Ondrias MR, Friedman JM. O2 and CO reactions with heme proteins: quantum yields and geminate recombination on picosecond time scales. Biochemistry 1990; 29:5537-45. [PMID: 2386783 DOI: 10.1021/bi00475a018] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Picosecond time-resolved absorption spectroscopy and low-temperature studies have been undertaken in order to understand the nature of the intrinsic quantum yields and geminate recombination of carbon monoxide and oxygen to hemoglobin and myoglobin. We find that the photoproduct yields at 40 ps and long times (minutes) after photolysis at 8 K are similar; however, the yield of oxygen photoproducts is 0.4 +/- 0.1 while the yield of carbon monoxide photoproducts is 1.0 +/- 0.1 for both myoglobin and hemoglobin. Measurements in the Soret, near-infrared, and far-IR are used to quantitate the photoproduct yields. These results call into question previous cryogenic kinetic studies of O2 recombination. Significant subnanosecond geminate recombination is observed in oxyhemoglobin down to 150 K, while below 100 K this geminate recombination disappears. The lower photoproduct yields for oxyheme protein complexes can be attributed to both subnanosecond and subpicosecond recombination events which are ligand and protein dynamics dependent.
Collapse
Affiliation(s)
- M R Chance
- Department of Chemistry, Georgetown University, Washington, D.C. 20057
| | | | | | | | | |
Collapse
|
37
|
Findsen EW, Ondrias MR. Transient and time-resolved optical studies of photolyzed carbonmonoxy hemoglobin and myoglobin. Photochem Photobiol 1990; 51:741-8. [PMID: 2195562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- E W Findsen
- Department of Chemistry, University of Toledo, OH 43606
| | | |
Collapse
|
38
|
Chavez MD, Courtney SH, Chance MR, Kiula D, Nocek J, Hoffman BM, Friedman JM, Ondrias MR. Structural and functional significance of inhomogeneous line broadening of band III in hemoglobin and Fe-Mn hybrid hemoglobins. Biochemistry 1990; 29:4844-52. [PMID: 2364063 DOI: 10.1021/bi00472a014] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Near-infrared spectra of hemoglobin and Fe-Mn hybrid hemoglobins have been obtained at cryogenic temperatures. The charge-transfer (a2u(pi)----dzy) transition at approximately 760 nm (band III) has been found to be a conformationally sensitive indicator of the heme-pocket geometry in these species. Temperature, protein tertiary and quaternary structure, chain heterogeneity, and ligand rebinding subsequent to CO photolysis all affect the line width and position of this transition. We conclude that the overall line shape of band III is derived from both subunit heterogeneity and conformational disorder within each subunit. A model is suggested that relates the observed pH dependence of the kinetic hole burning due to ligand rebinding to specific structural parameters of the proximal heme pocket that influence both the peak position and the inhomogeneous line shape of band III.
Collapse
Affiliation(s)
- M D Chavez
- Department of Chemistry, University of New Mexico, Albuquerque 78131
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Hobbs JD, Larsen RW, Meyer TE, Hazzard JH, Cusanovich MA, Ondrias MR. Resonance Raman characterization of Chromatium vinosum cytochrome c'. Effect of pH and comparison of equilibrium and photolyzed carbon monoxide species. Biochemistry 1990; 29:4166-74. [PMID: 2163273 DOI: 10.1021/bi00469a020] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Resonance Raman spectra of Chromatium vinosum cytochrome c' have been obtained for the five pH-dependent states of the protein [i.e., types I (pH 7), II (pH 10), and III (pH 12) of the ferric protein and type a (pH 7) and type n (pH 12) of the ferrous protein]. The raman spectra of type II and type a are consistent with those of high-spin, 5-coordinate heme proteins, such as deoxyhemoglobin, while spectra of type III and type n correspond more closely to those of low-spin, ferric and ferrous cytochrome c, respectively. Spectra of the CO-bound equilibrium species qualitatively resemble those of carbon monoxy human HbA. However, both the Fe-C and C = O stretching modes of the ligated species exhibit pH-dependent frequency shifts. Our data also indicate that CO photolysis is much more efficient at pH 7 than at pH 12. Moreover, the spectra of the photolytic transients suggest that unique, high-spin species are formed subsequent to CO photolysis from both type a and type n species.
Collapse
Affiliation(s)
- J D Hobbs
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | | | | | | | |
Collapse
|
40
|
Larsen RW, Chavez MD, Ondrias MR, Courtney SH, Friedman JM, Lin MJ, Hirsch RE. Dynamics and reactivity of HbXL99 alpha. A cross-linked hemoglobin derivative. J Biol Chem 1990; 265:4449-54. [PMID: 2307673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Resonance Raman spectroscopy, transient absorption, and fluroescence techniques have been employed to investigate the structure and dynamics of the alpha-cross-linked hemoglobin derivative, HbXL99 alpha. The resonance Raman spectra of the deoxy form of HbXL99 alpha are identical to those of native NbA (VFe-His approximately 222 cm-1), which exhibit a T-state (low affinity) structure regardless of solvent conditions. The resonance Raman spectra of the transient heme photoproduct resulting from CO photolysis from HbXL99 alpha appear to have structures intermediate between deoxy-T and ligand-bound R structures (VFe-His approximately 222 cm-1). Time-resolved resonance Raman data of HbXL99 alpha-CO show that complete CO recombination occurs after approximately 5 ms, with only a small amount of the CO-bound species reforming within approximately 200 ns (geminate recombination). Transient absorption spectra of HbXL99 alpha-O2 indicate that the extent of sub-nanosecond geminate recombination of O2 is also reduced in the cross-linked derivative relative to native HbA. The decrease in tryptophan fluorescence of HbXL99 alpha upon oxygenation further indicates that tertiary structural changes at the alpha 1-beta 2 interface upon ligation are apparently reduced, but not eliminated in the cross-linked derivative relative to HbA.
Collapse
Affiliation(s)
- R W Larsen
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | | | | | | | | | |
Collapse
|
41
|
Abstract
Modification of the CuA site in mammalian cytochrome c oxidase has been used to elucidate the functional role of this center in the catalytic cycle of the enzyme. Both heat treatment in detergents and chemical modification by p-(hydroxymercuri)benzoate (pHMB) convert CuA to a lower potential type II center and effectively remove the site from the electron-transfer pathway during turnover. In this study, resonance Raman spectroscopy has been employed to investigate the effects of these CuA modifications on the heme active sites. The Raman data indicate some environmental perturbation of the heme a3 chromophore in the modified derivatives. Only pHMB modification and SB-12 heat treatment produced significant effects in the Raman spectra of the fully reduced enzyme. These perturbations are much less evident in the spectra obtained within 10 ns of CO photolysis from the fully reduced species of the modified enzymes. Transient Raman studies further indicate that the half-time for CO religation in the modified enzymes is quite similar to that of the native protein.
Collapse
Affiliation(s)
- R W Larsen
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | | | | | |
Collapse
|
42
|
Hirasawa M, Gray KA, Ondrias MR, Larsen RW, Shaw RW, Morrow KJ, Knaff DB. Prosthetic group content and ligand binding properties of a spinach catalase. Biochim Biophys Acta 1989; 994:229-34. [PMID: 2537661 DOI: 10.1016/0167-4838(89)90298-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A recently discovered form of spinach catalase that contains both a novel heme and protoheme as prosthetic groups has been characterized using immunological and spectroscopic techniques. The enzyme appears to be a dimer of identical Mr 60,000 monomers. Extraction of the non-covalently bound prosthetic groups, followed by thin-layer chromatography of the extract, suggested that the novel heme contains four carboxylic acid side-chain groups. The resonance Raman spectrum of the resting enzyme indicates that the protoheme prosthetic group is five-coordinate and high-spin. The enzyme was shown to bind formate, azide and cyanide. Cyanide and azide binding to catalase are biphasic, suggesting the existence of two different binding sites for cyanide and azide in the enzyme. Results obtained from EPR and resonance Raman spectroscopies also support the hypothesis that two different ligand-binding sites are present in the enzyme. Western blots suggest that the Mr 60,000 peptide of the novel heme-containing catalase is similar or identical to that of a previously characterized, exclusively protoheme-containing, tetrameric catalase.
Collapse
Affiliation(s)
- M Hirasawa
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409
| | | | | | | | | | | | | |
Collapse
|
43
|
Alden RG, Satterlee JD, Mintorovitch J, Constantinidis I, Ondrias MR, Swanson BI. The effects of high pressure upon ligated and deoxyhemoglobins and myoglobin. An optical spectroscopic study. J Biol Chem 1989; 264:1933-40. [PMID: 2914887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The effects of high pressure (0.1-3.4 gigapascal (GPa)) on the ferrous heme active sites of human adult hemoglobin, sperm whale myoglobin, and Glycera dibranchiata hemoglobin (Fraction II) were probed using resonance Raman and absorption spectroscopies. High-to-low spin transitions of the heme iron occur for hemoglobin, myoglobin, and Glycera hemoglobin at 0.35, 0.75, and 0.50 GPa, respectively, for the deoxy species. These interspecies differences result from variations in the composition of the hemepockets and/or their rigidity to pressure-induced volume changes. Heme active sites initially bound to CO or O2 exhibit distinctive behavior at high pressures. For all proteins studied, O2 apparently dissociates from the heme at only moderately high pressure, while CO remains bound to the heme moiety even at extreme pressures. The Raman spectra demonstrate the differences in the ligated and deoxy species at 3.4 GPa in the high frequency region. Discrete changes (i.e. iron spin-state transitions and dissociation of O2) occur that are commensurate with the collapse of the distal pocket, while continuous shifts in the absorption and Raman spectra are observed at pressures above those required for pocket collapse.
Collapse
Affiliation(s)
- R G Alden
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | | | | | | | |
Collapse
|
44
|
Alden RG, Satterlee JD, Mintorovitch J, Constantinidis I, Ondrias MR, Swanson BI. The effects of high pressure upon ligated and deoxyhemoglobins and myoglobin. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)94123-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
45
|
Abstract
The heme-pocket dynamics subsequent to carbon monoxide photolysis from human hemoglobin have been monitored as a function of glycerol-water solvent composition with time-resolved resonance Raman spectroscopy. Prompt (geminate) ligand recombination rates and the transient heme-pocket geometry established within 10 ns after photolysis appear to be largely independent of solvent composition. The rate of relaxation of the transient geometry to an equilibrium deoxy configuration is, however, quite sensitive to solvent composition. These observations suggest that the former processes result from local, internal motions of the protein, while the relaxation dynamics of the proximal heme pocket are predicated upon more global protein motions that are dependent upon solvent viscosity.
Collapse
Affiliation(s)
- E W Findsen
- Department of Chemistry, University of New Mexico, Albuquerque 87131
| | | | | |
Collapse
|
46
|
Abstract
The interactions of ethanol and methanol with ferrihemoglobin were examined using resonance Raman spectroscopy. After binding either alcohol, the low-frequency resonance Raman spectra of human ferrihemoglobin are almost identical to the unperturbed spectrum except for shifts in the 309 cm-1 band to higher frequency by as much as 8 cm-1. The ethanol-induced shift is greater than that with methanol even though complex formation was less for ethanol than methanol. The spectral changes imply a site-specific, similar binding of these alcohols to ferrihemoglobin which may involve steric interactions. Possible assignments of the 309 cm-1 band to structural features as well as potential mechanisms of the alcohol-induced spectral changes are discussed.
Collapse
Affiliation(s)
- B B Muhoberac
- Department of Chemistry, Purdue University School of Science, Indiana University-Purdue University at Indianapolis 46223
| | | | | |
Collapse
|
47
|
Shelnutt JA, Findsen EW, Ondrias MR, Alston K. Axial Coordination in Nickel and Vanadium Porphyrins: Transient and Difference Raman Spectroscopy. ACTA ACUST UNITED AC 1987. [DOI: 10.1021/bk-1987-0344.ch024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Affiliation(s)
- J. A. Shelnutt
- Process Research Division 6254, Sandia National Laboratories, Albuquerque, NM 87185
| | - E. W. Findsen
- Department of Chemistry, University of New Mexico, Albuquerque, NM 87131
| | - M. R. Ondrias
- Department of Chemistry, University of New Mexico, Albuquerque, NM 87131
| | - K. Alston
- Department of Natural Sciences, Benedict College, Columbia, SC 29204
| |
Collapse
|
48
|
Carson SD, Wells CA, Findsen EW, Friedman JM, Ondrias MR. Interspecies variations in the transient heme species generated subsequent to CO photolysis from hemoglobins. J Biol Chem 1987; 262:3044-51. [PMID: 3818632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The structure, ligand binding kinetics, and thermodynamics of hemoglobin have been the subject of a great deal of investigation. However, the exact pathway(s) by which cooperative energetics are communicated within the protein remain undefined. The effects of interspecies variations in quaternary and tertiary structure, oxygen affinity, cooperativity, and ligand binding kinetics upon the overall ligand binding process are, therefore, of great importance in understanding and solving these problems. The demonstrated sensitivity of resonance Raman spectroscopy to heme structure and environment make it an ideal probe of ligand binding dynamics. It is possible to examine how specific vibrational modes change with time and correlate this with solution conditions and protein structural and conformational differences. Those modes which exhibit the greatest change with ligand photolysis are also indicative of possible paths of cooperative energy dissipation within the protein. The changes which occur in the vibrational modes of the heme within 10 ns of CO photolysis have been determined for a wide variety of mammalian and reptilian hemoglobins. The modes most affected by this process are, without exception, nu(Fe-His), nu4, and the substituent bending modes, delta(cb - s) and delta(cb - c alpha - c beta). Furthermore, a direct correlation exists between the shift in porphyrin pi electron density upon CO photolysis (as indicated by the transient changes in nu 4) and the Hill coefficient of cooperativity. The implications of those results concerning ligand binding cooperativity in hemoglobins are discussed.
Collapse
|
49
|
Gaul DF, Ondrias MR, Findsen EW, Palmer G, Olson JS, Davidson MW, Knaff DB. Spectroscopic and kinetic properties of an oxygen-binding heme protein from Chromatium vinosum. J Biol Chem 1987; 262:1144-7. [PMID: 3027081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Resonance Raman and electron paramagnetic resonance spectroscopy have been utilized to identify histidine as an axial heme ligand in a high spin, heme c-containing protein isolated from the photosynthetic purple sulfur bacterium Chromatium vinosum. Resonance Raman spectroscopy has also been used to characterize the CO adduct of the C. vinosum hemoprotein. Resonance Raman spectra of the heme site obtained within 10 ns of CO photolysis from the ferrous hemoprotein are virtually identical to those of the unligated protein, indicating that there is little or no rearrangement of the heme pocket in response to ligand photolysis. The equilibrium constant for CO binding to the ferrous hemeprotein was measured to be 1.7 X 10(-5) M-1 and the CO association rate constant determined to be 5.4 X 10(3) M-1 S-1. The quantum efficiency for photodissociation of the hemoprotein X CO complex was greater than or equal to 0.9.
Collapse
|
50
|
Gaul DF, Ondrias MR, Findsen EW, Palmer G, Olson JS, Davidson MW, Knaff DB. Spectroscopic and kinetic properties of an oxygen-binding heme protein from Chromatium vinosum. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(19)75762-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
|