1
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Field MJ, Oyala PH, Green MT. 17O Electron Nuclear Double Resonance Analysis of Compound I: Inverse Correlation between Oxygen Spin Population and Electron Donation. J Am Chem Soc 2022; 144:19272-19283. [PMID: 36240444 DOI: 10.1021/jacs.2c05459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Although the activation of inert C-H bonds by metal-oxo complexes has been widely studied, important questions remain, particularly regarding the role of oxygen spin population (i.e., unpaired electrons on the oxo ligand) in facilitating C-H bond cleavage. In order to shed light on this issue, we have utilized 17O electron nuclear double resonance spectroscopy to measure the oxygen spin populations of three compound I intermediates in heme enzymes with different reactivities toward C-H bonds: chloroperoxidase, cytochrome P450, and a selenolate (selenocysteinyl)-ligated cytochrome P450. The experimental data suggest an inverse correlation between oxygen spin population and electron donation from the axial ligand. We have explored the implications of this result using a Hückel-type molecular orbital model and constrained density functional theory calculations. These investigations have allowed us to examine the relationship between oxygen spin population, oxygen charge, electron donation from the axial ligand, and reactivity.
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Affiliation(s)
- Mackenzie J Field
- Department of Chemistry and Department of Molecular Biology and Biochemistry, University of California, Irvine, California92697, United States
| | - Paul H Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California91125, United States
| | - Michael T Green
- Department of Chemistry and Department of Molecular Biology and Biochemistry, University of California, Irvine, California92697, United States
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2
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You M, Liu L, Zhang W. The covalently bound diazo group as an infrared probe for hydrogen bonding environments. Phys Chem Chem Phys 2017; 19:19420-19426. [DOI: 10.1039/c7cp01867c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The bandwidth or position of diazo groups can probe the polarizability and HBA, or density of HBD groups.
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Affiliation(s)
- Min You
- Center for Advanced Quantum Studies
- Department of Physics and Applied Optics Beijing Area Major Laboratory
- Beijing Normal University
- Beijing
- China
| | - Liyuan Liu
- Center for Advanced Quantum Studies
- Department of Physics and Applied Optics Beijing Area Major Laboratory
- Beijing Normal University
- Beijing
- China
| | - Wenkai Zhang
- Center for Advanced Quantum Studies
- Department of Physics and Applied Optics Beijing Area Major Laboratory
- Beijing Normal University
- Beijing
- China
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3
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Kruglik SG, Yoo BK, Lambry JC, Martin JL, Negrerie M. Structural changes and picosecond to second dynamics of cytochrome c in interaction with nitric oxide in ferrous and ferric redox states. Phys Chem Chem Phys 2017; 19:21317-21334. [DOI: 10.1039/c7cp02634j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
After dissociation NO rebinds to Cyt c in 10 ps whereas Met80 rebinds in 5 μs after NO release from Cyt c. A complete view of heme – NO dynamics within 12 orders of magnitude of time in Cyt c is presented.
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Affiliation(s)
- Sergei G. Kruglik
- Laboratoire Jean Perrin
- Sorbonne Universités
- UPMC Univ. Paris 06
- CNRS
- 75005 Paris
| | - Byung-Kuk Yoo
- Laboratoire d'Optique et Biosciences
- INSERM
- Ecole Polytechnique
- 91128 Palaiseau
- France
| | | | - Jean-Louis Martin
- Laboratoire d'Optique et Biosciences
- INSERM
- Ecole Polytechnique
- 91128 Palaiseau
- France
| | - Michel Negrerie
- Laboratoire d'Optique et Biosciences
- INSERM
- Ecole Polytechnique
- 91128 Palaiseau
- France
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4
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Smith AT, Pazicni S, Marvin KA, Stevens DJ, Paulsen KM, Burstyn JN. Functional divergence of heme-thiolate proteins: a classification based on spectroscopic attributes. Chem Rev 2015; 115:2532-58. [PMID: 25763468 DOI: 10.1021/cr500056m] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aaron T Smith
- †Department of Molecular Biosciences, Northwestern University, 2205 Tech Drive, Evanston, Illinois 60208, United States
| | - Samuel Pazicni
- ‡Department of Chemistry, University of New Hampshire, 23 Academic Way, Durham, New Hampshire 03824, United States
| | - Katherine A Marvin
- §Department of Chemistry, Hendrix College, 1600 Washington Avenue, Conway, Arkansas 72032, United States
| | - Daniel J Stevens
- ∥Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Katherine M Paulsen
- ∥Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Judith N Burstyn
- ∥Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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5
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Ishimori K, Watanabe Y. Unique Heme Environmental Structures in Heme-regulated Proteins Using Heme as the Signaling Molecule. CHEM LETT 2014. [DOI: 10.1246/cl.140787] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
| | - Yuta Watanabe
- Department of Chemistry, Faculty of Science, Hokkaido University
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6
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Kumar S, Kumar V, Jain DC. Laser Raman Spectroscopic Studies on Hemeproteins in Epileptic Children. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/ojapps.2013.31018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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7
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Yoshida Y, Ishikawa H, Aono S, Mizutani Y. Structural dynamics of proximal heme pocket in HemAT-Bs associated with oxygen dissociation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:866-72. [DOI: 10.1016/j.bbapap.2012.04.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 04/14/2012] [Accepted: 04/20/2012] [Indexed: 11/30/2022]
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8
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Heme-protein vibrational couplings in cytochrome c provide a dynamic link that connects the heme-iron and the protein surface. Proc Natl Acad Sci U S A 2012; 109:8896-900. [PMID: 22619327 DOI: 10.1073/pnas.1200345109] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The active site of cytochrome c (Cyt c) consists of a heme covalently linked to a pentapeptide segment (Cys-X-X-Cys-His), which provides a link between the heme and the protein surface, where the redox partners of Cyt c bind. To elucidate the vibrational properties of heme c, nuclear resonance vibrational spectroscopy (NRVS) measurements were performed on (57)Fe-labeled ferric Hydrogenobacter thermophilus cytochrome c(552), including (13)C(8)-heme-, (13)C(5)(15)N-Met-, and (13)C(15)N-polypeptide (pp)-labeled samples, revealing heme-based vibrational modes in the 200- to 450-cm(-1) spectral region. Simulations of the NRVS spectra of H. thermophilus cytochrome c(552) allowed for a complete assignment of the Fe vibrational spectrum of the protein-bound heme, as well as the quantitative determination of the amount of mixing between local heme vibrations and pp modes from the Cys-X-X-Cys-His motif. These results provide the basis to propose that heme-pp vibrational dynamic couplings play a role in electron transfer (ET) by coupling vibrations of the heme directly to vibrations of the pp at the protein-protein interface. This could allow for the direct transduction of the thermal (vibrational) energy from the protein surface to the heme that is released on protein/protein complex formation, or it could modulate the heme vibrations in the protein/protein complex to minimize reorganization energy. Both mechanisms lower energy barriers for ET. Notably, the conformation of the distal Met side chain is fine-tuned in the protein to localize heme-pp mixed vibrations within the 250- to 400-cm(-1) spectral region. These findings point to a particular orientation of the distal Met that maximizes ET.
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9
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Uchida T, Sagami I, Shimizu T, Ishimori K, Kitagawa T. Effects of the bHLH domain on axial coordination of heme in the PAS-A domain of neuronal PAS domain protein 2 (NPAS2): Conversion from His119/Cys170 coordination to His119/His171 coordination. J Inorg Biochem 2012; 108:188-95. [DOI: 10.1016/j.jinorgbio.2011.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 12/19/2011] [Accepted: 12/19/2011] [Indexed: 10/14/2022]
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10
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Ishikawa H, Nakagaki M, Bamba A, Uchida T, Hori H, O'Brian MR, Iwai K, Ishimori K. Unusual heme binding in the bacterial iron response regulator protein: spectral characterization of heme binding to the heme regulatory motif. Biochemistry 2011; 50:1016-22. [PMID: 21192735 DOI: 10.1021/bi101895r] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We characterized heme binding in the bacterial iron response regulator (Irr) protein, which is a simple heme-regulated protein having a single "heme-regulatory motif", HRM, and plays a key role in the iron homeostasis of a nitrogen-fixing bacterium. The heme titration to wild-type and mutant Irr clearly showed that Irr has two heme binding sites: one of the heme binding sites is in the HRM, where (29)Cys is the axial ligand, and the other one, the secondary heme binding site, is located outside of the HRM. The Raman line for the Fe-S stretching mode observed at 333 cm(-1) unambiguously confirmed heme binding to Cys. The lower frequency of the Fe-S stretching mode corresponds to the weaker Fe-S bond, and the broad Raman line of the Fe-S bond suggests multiple configurations of heme binding. These structural characteristics are definitely different from those of typical hemoproteins. The unusual heme binding in Irr was also evident in the EPR spectra. The characteristic g-values of the 5-coordinate Cys-ligated heme and 6-coordinate His/His-ligated heme were observed, while the multiple configurations of heme binding were also confirmed. Such multiple heme configurations are not encountered for typical hemoproteins where the heme functions as the active center. Therefore, we conclude that heme binding to HRM in the heme-regulated protein, Irr, is quite different from that in conventional hemoproteins but characteristic of heme-regulated proteins using heme as the signaling molecule.
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Affiliation(s)
- Haruto Ishikawa
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto 615-8530, Japan
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11
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Gardner JD, Pierce BS, Fox BG, Brunold TC. Spectroscopic and computational characterization of substrate-bound mouse cysteine dioxygenase: nature of the ferrous and ferric cysteine adducts and mechanistic implications. Biochemistry 2010; 49:6033-41. [PMID: 20397631 DOI: 10.1021/bi100189h] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cysteine dioxygenase (CDO) is a mononuclear non-heme Fe-dependent dioxygenase that catalyzes the initial step of oxidative cysteine catabolism. Its active site consists of an Fe(II) ion ligated by three histidine residues from the protein, an interesting variation on the more common 2-His-1-carboxylate motif found in many other non-heme Fe(II)-dependent enzymes. Multiple structural and kinetic studies of CDO have been carried out recently, resulting in a variety of proposed catalytic mechanisms; however, many open questions remain regarding the structure/function relationships of this vital enzyme. In this study, resting and substrate-bound forms of CDO in the Fe(II) and Fe(III) states, both of which are proposed to have important roles in this enzyme's catalytic mechanism, were characterized by utilizing various spectroscopic methods. The nature of the substrate/active site interactions was also explored using the cysteine analogue selenocysteine (Sec). Our electronic absorption, magnetic circular dichroism, and resonance Raman data exhibit features characteristic of direct S (or Se) ligation to both the high-spin Fe(II) and Fe(III) active site ions. The resulting Cys- (or Sec-) bound species were modeled and further characterized using density functional theory computations to generate experimentally validated geometric and electronic structure descriptions. Collectively, our results yield a more complete description of several catalytically relevant species and provide support for a reaction mechanism similar to that established for many structurally related 2-His-1-carboxylate Fe(II)-dependent dioxygenases.
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Affiliation(s)
- Jessica D Gardner
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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12
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Nicoletti FP, Comandini A, Bonamore A, Boechi L, Boubeta FM, Feis A, Smulevich G, Boffi A. Sulfide binding properties of truncated hemoglobins. Biochemistry 2010; 49:2269-78. [PMID: 20102180 DOI: 10.1021/bi901671d] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The truncated hemoglobins from Bacillus subtilis (Bs-trHb) and Thermobifida fusca (Tf-trHb) have been shown to form high-affinity complexes with hydrogen sulfide in their ferric state. The recombinant proteins, as extracted from Escherichia coli cells after overexpression, are indeed partially saturated with sulfide, and even highly purified samples still contain a small but significant amount of iron-bound sulfide. Thus, a complete thermodynamic and kinetic study has been undertaken by means of equilibrium and kinetic displacement experiments to assess the relevant sulfide binding parameters. The body of experimental data indicates that both proteins possess a high affinity for hydrogen sulfide (K = 5.0 x 10(6) and 2.8 x 10(6) M(-1) for Bs-trHb and Tf-trHb, respectively, at pH 7.0), though lower with respect to that reported previously for the sulfide avid Lucina pectinata I hemoglobins (2.9 x 10(8) M(-1)). From the kinetic point of view, the overall high affinity resides in the slow rate of sulfide release, attributed to hydrogen bonding stabilization of the bound ligand by distal residue WG8. A set of point mutants in which these residues have been replaced with Phe indicates that the WG8 residue represents the major kinetic barrier to the escape of the bound sulfide species. Accordingly, classical molecular dynamics simulations of SH(-)-bound ferric Tf-trHb show that WG8 plays a key role in the stabilization of coordinated SH(-) whereas the YCD1 and YB10 contributions are negligible. Interestingly, the triple Tf-trHb mutant bearing only Phe residues in the relevant B10, G8, and CD1 positions is endowed with a higher overall affinity for sulfide characterized by a very fast second-order rate constant and 2 order of magnitude faster kinetics of sulfide release with respect to the wild-type protein. Resonance Raman spectroscopy data indicate that the sulfide adducts are typical of a ferric iron low-spin derivative. In analogy with other low-spin ferric sulfide adducts, the strong band at 375 cm(-1) is tentatively assigned to a Fe-S stretching band. The high affinity for hydrogen sulfide is thought to have a possible physiological significance as H(2)S is produced in bacteria at metabolic steps involved in cysteine biosynthesis and hence in thiol redox homeostasis.
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Affiliation(s)
- Francesco P Nicoletti
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino (FI), Italy
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13
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Leu BM, Ching TH, Zhao J, Sturhahn W, Alp EE, Sage JT. Vibrational dynamics of iron in cytochrome C. J Phys Chem B 2009; 113:2193-200. [PMID: 19173569 DOI: 10.1021/jp806574t] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nuclear resonance vibrational spectroscopy (NRVS) and Raman spectroscopy on (54)Fe- and (57)Fe-enriched cytochrome c (cyt c) identify multiple bands involving vibrations of the heme Fe. Comparison with predictions from Fe isotope shifts reveals that 70% of the NRVS signal in the 300-450 cm(-1) frequency range corresponds to vibrations resolved in Soret-enhanced Raman spectra. This frequency range dominates the "stiffness", an effective force constant determined by the Fe vibrational density of states (VDOS), which measures the strength of nearest-neighbor interactions with Fe. The stiffness of the low-spin Fe environment in both oxidation states of cyt c significantly exceeds that for the high-spin Fe in deoxymyoglobin, where the 200-300 cm(-1) frequency range dominates the VDOS. This situation is reflected in the shorter Fe-ligand bond lengths in the former with respect to the latter. The longer Fe-S(Met80) in oxidized cyt c with respect to reduced cyt c leads to a decrease in the stiffness of the iron environment upon oxidation. Comparison with NRVS measurements allows us to assess assignments for vibrational modes resolved in this region of the heme Raman spectrum. We consider the possibility that the 372 cm(-1) band in reduced cyt c involves the Fe-S(Met80) bond.
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Affiliation(s)
- Bogdan M Leu
- Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts 02115, USA
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14
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Chen H, Hirao H, Derat E, Schlichting I, Shaik S. Quantum Mechanical/Molecular Mechanical Study on the Mechanisms of Compound I Formation in the Catalytic Cycle of Chloroperoxidase: An Overview on Heme Enzymes. J Phys Chem B 2008; 112:9490-500. [DOI: 10.1021/jp803010f] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hui Chen
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel, and Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Hajime Hirao
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel, and Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Etienne Derat
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel, and Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Ilme Schlichting
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel, and Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Sason Shaik
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel, and Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
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15
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Gruia F, Ionascu D, Kubo M, Ye X, Dawson J, Osborne RL, Sligar SG, Denisov I, Das A, Poulos TL, Terner J, Champion PM. Low-frequency dynamics of Caldariomyces fumago chloroperoxidase probed by femtosecond coherence spectroscopy. Biochemistry 2008; 47:5156-67. [PMID: 18407660 DOI: 10.1021/bi7025485] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultrafast laser spectroscopy techniques are used to measure the low-frequency vibrational coherence spectra and nitric oxide rebinding kinetics of Caldariomyces fumago chloroperoxidase (CPO). Comparisons of the CPO coherence spectra with those of other heme species are made to gauge the protein-specific nature of the low-frequency spectra. The coherence spectrum of native CPO is dominated by a mode that appears near 32-33 cm(-1) at all excitation wavelengths, with a phase that is consistent with a ground-state Raman-excited vibrational wavepacket. On the basis of a normal coordinate structural decomposition (NSD) analysis, we assign this feature to the thiolate-bound heme doming mode. Spectral resolution of the probe pulse ("detuned" detection) reveals a mode at 349 cm(-1), which has been previously assigned using Raman spectroscopy to the Fe-S stretching mode of native CPO. The ferrous species displays a larger degree of spectral inhomogeneity than the ferric species, as reflected by multiple shoulders in the optical absorption spectra. The inhomogeneities are revealed by changes in the coherence spectra at different excitation wavelengths. The appearance of a mode close to 220 cm(-1) in the coherence spectrum of reduced CPO excited at 440 nm suggests that a subpopulation of five coordinated histidine-ligated hemes is present in the ferrous state at a physiologically relevant pH. A significant increase in the amplitude of the coherence signal is observed for the resonance with the 440 nm subpopulation. Kinetics measurements reveal that nitric oxide binding to ferric and ferrous CPO can be described as a single-exponential process, with rebinding time constants of 29.4 +/- 1 and 9.3 +/- 1 ps, respectively. This is very similar to results previously reported for nitric oxide binding to horseradish peroxidase.
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Affiliation(s)
- Flaviu Gruia
- Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts 02115, USA
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16
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Tosha T, Kagawa N, Arase M, Waterman MR, Kitagawa T. Interaction between substrate and oxygen ligand responsible for effective O-O bond cleavage in bovine cytochrome P450 steroid 21-hydroxylase proved by Raman spectroscopy. J Biol Chem 2007; 283:3708-17. [PMID: 18032381 DOI: 10.1074/jbc.m707338200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We investigated structural and functional properties of bovine cytochrome P450 steroid 21-hydroxylase (P450c21), which catalyzes hydroxylation at C-21 of progesterone and 17alpha-hydroxyprogesterone. The uncoupled H(2)O(2) formation was higher in the hydroxylation of progesterone (26% of NADPH consumed) than that of 17alpha-hydroxyprogesterone (15% of NADPH consumed), indicating that 17alpha-hydroxyprogesterone can better facilitate the O-O bond scission. In relation to this, it is noted that the O-O stretching mode (nu(O-O)) of the oxygen complex of P450c21 was sensitive to the substrate; the progesterone- or 17alpha-hydroxyprogesterone-bound enzyme gave single (at 1137 cm(-1)) or split nu(O-O) bands (at 1124 and 1138 cm(-1)), respectively, demonstrating the presence of two forms for the latter. In contrast to nu(O-O), no corresponding difference was observed for the Fe-O(2) stretching mode between two different substrate-bound forms. The Fe-S(Cys) stretching mode in the ferric state was also identical (349 cm(-1)) for each substrate-bound form, suggesting that modulation through the axial thiolate by the substrate is unlikely. Therefore, it is deduced that the hydroxyl group at C-17 of 17alpha-hydroxyprogesterone forms a hydrogen bond with the terminal oxygen atom of the FeOO complex in one form, yielding a lower nu(O-O) frequency with higher reactivity for O-O cleavage, whereas the other form in which the substrate does not provide a hydrogen bond to the oxygen ligand is essentially the same between the two kinds of substrates. In the hydrogen-bonded species, the substrate changes the geometry of the FeOO moiety, thereby performing the hydroxylation reaction more effectively in 17alpha-hydroxyprogesterone than in progesterone.
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Affiliation(s)
- Takehiko Tosha
- Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
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17
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Clay MD, Jenney FE, Noh HJ, Hagedoorn PL, Adams MWW, Johnson MK. Resonance Raman characterization of the mononuclear iron active-site vibrations and putative electron transport pathways in Pyrococcus furiosus superoxide reductase. Biochemistry 2002; 41:9833-41. [PMID: 12146949 DOI: 10.1021/bi025833b] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The resonance Raman spectrum of oxidized wild-type P. furiosus SOR at pH 7.5 and 10.5 has been investigated using excitation wavelengths between 406 and 676 nm, and vibrational modes have been assigned on the basis of isotope shifts resulting from global replacements of (32)S with (34)S, (14)N with (15)N, (56)Fe with (54)Fe, and exchange into a H(2)(18)O buffer. The results are interpreted in terms of the crystallographically defined active-site structure involving a six-coordinate mononuclear Fe center with four equatorial histidine ligands and axial cysteine and monodentate glutamate ligands (Yeh, A. P., Hu, Y., Jenney, F. E., Adams, M. W. W., and Rees, D. C. (2000) Biochemistry 39, 2499-2508). Excitation into the intense (Cys)S(p(pi))-to-Fe(d(pi)) CT transition centered at 660 nm results in strong enhancement of modes at 298 cm(-1) and 323 cm(-1) that are assigned to extensively mixed cysteine S-C(beta)-C(alpha) bending and Fe-S(Cys) stretching modes, respectively. All other higher-energy vibrational modes are readily assigned to overtone or combination bands or to fundamentals corresponding to internal modes of the ligated cysteine. Weak enhancement of Fe-N(His) stretching modes is observed in the 200-250 cm(-1) region. The enhancement of internal cysteine modes and Fe-N(His) stretching modes are a consequence of a near-planar Fe-S-C(beta)-C(alpha)-N unit for the coordinated cysteine and significant (His)N(p(pi))-Fe(d(xy))-(Cys)S(p(pi)) orbital overlap, respectively, and have close parallels to type 1 copper proteins. By analogy with type 1 copper proteins, putative superexchange electron-transfer pathways to the mononuclear Fe active site are identified involving either the tyrosine and cysteine residues or the solvent-exposed deltaN histidine residue in a Y-C-X-X-H arrangement. Studies of wild-type at pH 10.5 and the E14A variant indicate that the resonance Raman spectrum is remarkably insensitive to changes in the ligand trans to cysteine and hence are inconclusive concerning the origin of the alkaline transition and the nature of sixth Fe ligand in the E14A variant.
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Affiliation(s)
- Michael D Clay
- Department of Chemistry, Center for Metalloenzyme Studies, University of Georgia, Athens, GA 30602, USA
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18
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Denisov IG, Hung SC, Weiss KE, McLean MA, Shiro Y, Park SY, Champion PM, Sligar SG. Characterization of the oxygenated intermediate of the thermophilic cytochrome P450 CYP119. J Inorg Biochem 2001; 87:215-26. [PMID: 11744059 DOI: 10.1016/s0162-0134(01)00328-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Using UV-Vis, resonance Raman, and EPR spectroscopy we have studied the properties of the oxygenated ferrous cytochrome P450 from Sulfolobus solfataricus, (CYP119). The recently determined crystal structure of CYP119 is compared with other available structures of P450s, and detailed structural and spectroscopic analyses are reported. With several structural similarities to CYP102, such as in-plane iron position and a shorter iron-proximal ligand bond, CYP119 shows low-spin conformation preference in the ferric form and partially in the ferrous form at low temperatures. These structural features can explain the fast autoxidation of the oxyferrous complex of CYP119. Finally, we report the first UV-Vis and EPR spectra of the cryoradiolytically reduced oxygenated intermediate of CYP119. The primary reduced intermediate, a hydroperoxo-ferric complex of CYP119, undergoes a 'peroxide shunt' pathway during gradual annealing at 170-195 K and returns to the low-spin ferric form.
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Affiliation(s)
- I G Denisov
- Departments of Biochemistry and Chemistry, College of Medicine, and The Beckman Institute, University of Illinois, Urbana, IL 61801, USA
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Couture M, Adak S, Stuehr DJ, Rousseau DL. Regulation of the properties of the heme-NO complexes in nitric-oxide synthase by hydrogen bonding to the proximal cysteine. J Biol Chem 2001; 276:38280-8. [PMID: 11479310 DOI: 10.1074/jbc.m105341200] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nitric-oxide synthase (NOS) catalyzes the formation of NO and citrulline from l-arginine and oxygen. However, the NO so formed has been found to auto-inhibit the enzymatic activity significantly. We hypothesized that the NO reactivity is in part controlled by hydrogen bonding between the conserved tryptophan residue (position 409 in the neuronal isoform of NOS (nNOS)) and the cysteine residue that forms the proximal bond to the heme. By using resonance Raman spectroscopy and NO as a probe of the heme environment, we show that in the W409F and W409Y mutants of the oxygenase domain of the neuronal enzyme (nNOSox), the Fe-NO bond in the Fe3+NO complex is weaker than in the wild type enzyme, consistent with the loss of a hydrogen bond on the sulfur atom of the proximal cysteine residue. The weaker Fe-NO bond in the W409F and W409Y mutants might result in a faster rate of NO dissociation from the ferric heme in the Trp-409 mutants as compared with the wild type enzyme, which could contribute to the lower accumulation of the inhibitory NO-bound complexes observed during catalysis with the Trp-409 mutants (Adak, S., Crooks, C., Wang, Q., Crane, B. R., Tainer, J. A., Getzoff, E. D., and Stuehr, D. J. (1999) J. Biol. Chem. 274, 26907-26911). The optical and resonance Raman spectra of the Fe2+NO complexes of the Trp-409 mutants differ from those of the wild type enzyme and indicate that a significant population of a five-coordinate Fe2+NO complex is present. These data show that the hydrogen bond provided by the Trp-409 residue is necessary to maintain the thiolate coordination when NO binds to the ferrous heme. Taken together our results indicate that the heme environment on the proximal side of nNOS is critical for the formation of a stable iron-cysteine bond and for the control of the electronic properties of heme-NO complexes.
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Affiliation(s)
- M Couture
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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20
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Ambert-Balay K, Dougherty M, Tien M. Reactivity of manganese peroxidase: site-directed mutagenesis of residues in proximity to the porphyrin ring. Arch Biochem Biophys 2000; 382:89-94. [PMID: 11051101 DOI: 10.1006/abbi.2000.2000] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to determine the effect of heme pocket hydrophobicity on the reactivity of manganese peroxidase. Residues within 5 A of the heme active site were identified. From this group, Leu169 and Ser172 were selected and mutated to Phe and Ala, respectively. The mutant proteins were then characterized by steady-state kinetics. Whereas the Leu169Phe mutation had little, if any, effect on activity, the Ser172Ala mutation decreased kcat and also the specificity constant (kcat/Km) for Mn2+, but not H2O2. Transient-state studies indicated that the mutation affected only the reactions of compound II. These results indicate that compound II is the most sensitive to changes in the heme environment.
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Affiliation(s)
- K Ambert-Balay
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park 16802, USA
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21
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Vogel KM, Kozlowski PM, Zgierski MZ, Spiro TG. Role of the axial ligand in hemeCO backbonding; DFT analysis of vibrational data. Inorganica Chim Acta 2000. [DOI: 10.1016/s0020-1693(99)00253-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
Enantiopure epoxides, as well as their corresponding vicinal diols, are valuable intermediates in fine organic synthesis, in particular for the preparation of biologically active compounds. The necessity of preparing such target molecules in an optically pure form has triggered much research, leading to the emergence of various new methods based on either conventional chemistry or enzymatically catalyzed reactions. In this review, we focus on the biocatalytic approaches, which include direct epoxidation of olefinic double bonds as well as indirect biocatalytic methods, and which allow for the synthesis of these important chiral building blocks in enantiomerically enriched or even enantiopure form.
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Affiliation(s)
- A Archelas
- Groupe Biocatalyse et Chimie Fine, ERS 157 associée au CNRS, Faculté des Sciences de Luminy, Marseille, France
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24
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25
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Resonance Raman spectroscopy of the catalytic intermediates and derivatives of chloroperoxidase from Caldariomyces fumago. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36742-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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26
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Hu S, Kincaid J. Heme active-site structural characterization of chloroperoxidase by resonance Raman spectroscopy. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53237-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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28
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Egawa T, Miki H, Ogura T, Makino R, Ishimura Y, Kitagawa T. Observation of the FeIV=O stretching Raman band for a thiolate-ligated heme protein. Compound I of chloroperoxidase. FEBS Lett 1992; 305:206-8. [PMID: 1299616 DOI: 10.1016/0014-5793(92)80668-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The FeIV=O stretching vibration has never been identified for a cysteine-coordinated heme enzyme. In this study, resonance Raman and visible absorption spectra were observed simultaneously for transient species in the catalytic reaction of chloroperoxidase with hydrogen peroxide by using our original apparatus for mixed-flow and Raman/absorption simultaneous measurements. For the first intermediate, the FeIV=O stretching Raman band was observed at 790 cm-1, which shifted to 756 cm-1 with the 18O derivative, but the v4 band was too weak to be identified. This suggested the formation of an oxoferryl porphyrin pi cation radical. The second intermediate gave an intense v4 band at 1,372 cm-1 but no oxygen isotope-sensitive Raman band, suggesting oxygen exchange with bulk water.
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Affiliation(s)
- T Egawa
- Institute for Molecular Science, Okazaki National Research Institutes, Japan
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29
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Dugad LB, Wang X, Wang CC, Lukat GS, Goff HM. Proton nuclear Overhauser effect study of the heme active site structure of chloroperoxidase. Biochemistry 1992; 31:1651-5. [PMID: 1737022 DOI: 10.1021/bi00121a011] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Chloroperoxidase, a glycoprotein from the mold Caldariomyces fumago, has been investigated in its ferric low-spin cyanide-ligated form through use of nuclear Overhauser effect (NOE) spectroscopy to provide information on the heme pocket electronic/molecular structure. Spin-lattice relaxation times for the hyperfine-shifted heme resonances were found to be three times less than those in horseradish peroxidase. This must reflect a slower electronic relaxation rate for chloroperoxidase than for horseradish peroxidase as a consequence of axial ligation of cysteine in the former versus histidine in the latter enzyme. Isoenzymes A1 and A2 of chloroperoxidase show the largest chemical shift differences near the heme propionate on the basis of NOE measurements. This suggests that the primary structure differences for the two isoenzymes are communicated to the heme group through the ring propionate substituents. A downfield peak has been detected in chloroperoxidase with chemical shift, T1, and line width characteristics similar to those of the C epsilon-H proton of the distal histidine residue. The NOE pattern and T1's of the peaks in the 0.0 to -5.0 ppm upfield region are consistent with the presence of an arginine amino acid residue in the heme pocket near either the 1-CH3 or 3-CH3 group. Existence of catalytically important distal histidine and arginine amino acid residues in chloroperoxidase shows it to be structurally similar to peroxidases rather than to the often compared monooxygenase, cytochrome P-450. This result supports the earlier conclusions of Sono et al. [Sono, M., Dawson, J.H., Hall, K., & Hager, L.P. (1986) Biochemistry 25, 347-356].
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Affiliation(s)
- L B Dugad
- Department of Chemistry, University of Iowa, Iowa City 52242
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30
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Haloperoxidases: Their Properties and Their Use in Organic Synthesis. ADVANCES IN APPLIED MICROBIOLOGY 1992. [DOI: 10.1016/s0065-2164(08)70252-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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31
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Sono M, Hager LP, Dawson JH. Electron paramagnetic resonance investigations of exogenous ligand complexes of low-spin ferric chloroperoxidase: further support for endogenous thiolate ligation to the heme iron. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1078:351-9. [PMID: 1650250 DOI: 10.1016/0167-4838(91)90156-t] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Previous spectroscopic studies of chloroperoxidase have provided evidence for endogenous thiolate sulfur donor ligation to the central heme iron of the enzyme. This conclusion is further supported by recent DNA sequence data which revealed the existence of a third cysteine residue (in addition to a disulfide pair detected earlier) in the protein available for coordination to the heme iron. Thus, chloroperoxidase shares many spectroscopic properties with cytochrome P-450, the only other known thiolate-ligated heme protein. Surprisingly, a previous electron paramagnetic resonance (EPR) study of low-spin ferric chloroperoxidase-ligand complexes (Hollenberg, P.F., Hager, L.P., Blumberg, W.E. and Peisach, J. (1980) J. Biol. Chem. 255, 4801-4807) was unable to provide clear support for the presence of a thiolate ligand, although sulfur coordination was implicated. This was, in part, because an insufficient number of complexes was examined. In this work, we have significantly expanded upon the previous EPR study by using an extensive variety of over twenty exogenous ligands including carbon, nitrogen, oxygen, phosphorus and sulfur donors. Crystal field analysis, using the procedure of Blumberg and Peisach, of the present data in comparison with data for analogous complexes of cytochrome P-450-CAM, thiolate-ligated heme model systems, and myoglobin, is clearly indicative of endogenous thiolate ligation for chloroperoxidase. In addition, the UV-visible absorption and EPR spectral data suggest that a carboxylate ligand is a possible candidate for the endogenous sixth ligand to the heme iron that is responsible for the reversible conversion of ferric chloroperoxidase from high-spin to low-spin at low temperatures (less than 200 K).
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Affiliation(s)
- M Sono
- Department of Chemistry, University of South Carolina, Columbia 29208
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32
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Park KD, Guo KM, Adebodun F, Chiu ML, Sligar SG, Oldfield E. Distal and proximal ligand interactions in heme proteins: correlations between C-O and Fe-C vibrational frequencies, oxygen-17 and carbon-13 nuclear magnetic resonance chemical shifts, and oxygen-17 nuclear quadrupole coupling constants in C17O- and 13CO-labeled species. Biochemistry 1991; 30:2333-47. [PMID: 2001365 DOI: 10.1021/bi00223a007] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have obtained the oxygen-17 nuclear magnetic resonance (NMR) spectra of a variety of C17O-labeled heme proteins, including sperm whale (Physeter catodon) myoglobin, two synthetic sperm whale myoglobin mutants (His E7----Val E7; His E7----Phe E7), adult human hemoglobin, rabbit (Oryctolagus cuniculus) hemoglobin, horseradish (Cochlearia armoracia) peroxidase (E.C. 1.11.1.7) isoenzymes A and C, and Caldariomyces fumago chloroperoxidase (E.C. 1.11.1.10), in some cases as a function of pH, and have determined their isotropic 17O NMR chemical shifts, delta i, and spin-lattice relaxation times, T1. We have also obtained similar results on a picket fence prophyrin, [5,10,15,20-tetrakis(alpha, alpha, alpha, alpha, alpha-pivalamidophenyl)porphyrinato]iron(II) (1-MeIm)CO, both in solution and in the solid state. Our results show an excellent correlation between the infrared C-O vibrational frequencies, v(C-O), and delta i, between v(C-O) and the 17O nuclear quadrupole coupling constant (e2qQ/h, derived from T1), and as expected between e2qQ/h and delta i. Taken together with the work of others on the 13C NMR of 13CO-labeled proteins, where we find an excellent correlation between delta i(13C) and v(Fe-C), our results suggest that IR and NMR measurements reflect the same interaction, which is thought to be primarily the degree of pi-back-bonding from Fe d to CO pi* orbitals, as outlined previously [Li, X.-Y., & Spiro, T.G. (1988) J. Am. Chem. Soc. 110, 6024]. The modulation of this interaction by the local charge field of the distal heme residue (histidine, glutamine, arginine, and possibly lysine) in a variety of species and mutants, as reflected in the NMR and IR measurements, is discussed, as is the effect of cysteine as the proximal heme ligand.
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Affiliation(s)
- K D Park
- School of Chemical Sciences, University of Illinois, Urbana-Champaign 61801
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33
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Lukat GS, Goff HM. A nuclear magnetic resonance study of axial ligation for the reduced states of chloroperoxidase, cytochrome P-450cam, and porphinatoiron(II) thiolate complexes. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1037:351-9. [PMID: 2310751 DOI: 10.1016/0167-4838(90)90037-g] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The reduced forms of cytochrome P-450cam and chloroperoxidase were examined by proton NMR spectroscopy. The pH and temperature dependences of the proton NMR spectra of both ferrous enzymes are reported. A series of alkyl mercaptide complexes of both synthetic and natural-derivative iron(II) porphyrins was also examined. The proton NMR spectra of these complexes facilitated the assignment of resonances due to the axial ligand in the model compounds on the basis of their isotropic shifts and multiplicities. Comparison of model compound data with that for the reduced enzymes supports assignment of the methylene protons for the axial cysteinate of ferrous cytochrome P-450cam and ferrous chloroperoxidase to proton NMR resonances at 279 and 200 ppm (pH 7.0, 298K), respectively. Differences in the active site structure of the two enzymes are further demonstrated by 15N-NMR spectroscopy of the cyanide complexes of the ferric forms.
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Affiliation(s)
- G S Lukat
- Department of Chemistry, University of Iowa, Iowa City 52242
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34
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Palaniappan V, Terner J. Resonance Raman Spectroscopy of Horseradish Peroxidase Derivatives and Intermediates with Excitation in the Near Ultraviolet. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)71585-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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35
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36
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Lee HC, Cummings K, Hall K, Hager LP, Oldfield E. Oxygen-17 nuclear magnetic resonance spectroscopic studies of carbonmonoxyperoxidases. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37566-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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37
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Abstract
Structural factors that influence functional properties are examined in the case of four heme enzymes: cytochrome P-450, chloroperoxidase, horseradish peroxidase, and secondary amine mono-oxygenase. The identity of the axial ligand, the nature of the heme environment, and the steric accessibility of the heme iron and heme edge combine to play major roles in determining the reactivity of each enzyme. The importance of synthetic porphyrin models in understanding the properties of the protein-free metal center is emphasized. The conclusions described herein have been derived from studies at the interface between biological and inorganic chemistry.
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Affiliation(s)
- J H Dawson
- Department of Chemistry, University of South Carolina, Columbia 29208
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38
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Bangcharoenpaurpong O, Champion PM, Martinis SA, Sligar SG. Investigations of the resonance Raman excitation profiles of cytochromeP450cam. J Chem Phys 1987. [DOI: 10.1063/1.452885] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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39
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Kenigsberg P, Fang GH, Hager LP. Post-translational modifications of chloroperoxidase from Caldariomyces fumago. Arch Biochem Biophys 1987; 254:409-15. [PMID: 2883934 DOI: 10.1016/0003-9861(87)90118-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The secreted form of the halogenating glycoenzyme, chloroperoxidase, is processed from a precursor containing a 21-residue-long, moderately hydrophobic signal sequence, at an atypical Gln-Glu peptide bond. Following cleavage, the N-terminal glutamic acid readily cyclizes into pyroglutamic acid. Chloroperoxidase contains two high-mannose N-glycosylation sites, identified as Asn12 and Asn213. Other modifications include deamidation of residues Asn13, Asn198, and Gln183 into the corresponding acids. Finally, structural arguments suggest that Cys87 may be the axial heme ligand in the active site of chloroperoxidase.
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40
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Fang GH, Kenigsberg P, Axley MJ, Nuell M, Hager LP. Cloning and sequencing of chloroperoxidase cDNA. Nucleic Acids Res 1986; 14:8061-71. [PMID: 3774552 PMCID: PMC311834 DOI: 10.1093/nar/14.20.8061] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
An oligod-d(T) 12-18 primed cDNA library has been prepared from Caldariomyces fumago mRNA. A clone containing a full-length insert was sequenced on the supercoiled plasmid, pBR322. The complete primary sequence of chloroperoxidase has been derived. We have also determined about 73% of the peptide sequence by amino acid sequencing. The DNA sequence data matches all of the available known peptide sequences. The mature polypeptide contains 300 amino acids having a combined molecular weight of 32,974 daltons. A putative signal peptide of 21 amino acids is proposed from DNA sequence data. The chloroperoxidase gene encodes three potential glycosylation sites recognized as Asn-X-Thr/Ser sequences. Three cysteine residues are found in the protein sequence. A small region around Cys87 bears a minimal homology to the active site of cytochrome P450cam. No other heme protein homologues can be detected. We propose that Cys87 serves as a thiolate ligand to the iron of heme prosthetic group. A rare arginine codon, AGG, is used three times out of twelve in contrast to the very infrequent use of this codon in E. coli or yeast.
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