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Zhong F, Albert T, Moënne-Loccoz P, Pletneva EV. Influence of the Interdomain Interface on Structural and Redox Properties of Multiheme Proteins. Inorg Chem 2022; 61:20949-20963. [PMID: 36493379 PMCID: PMC11034829 DOI: 10.1021/acs.inorgchem.2c03427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Multiheme proteins are important in energy conversion and biogeochemical cycles of nitrogen and sulfur. A diheme cytochrome c4 (c4) was used as a model to elucidate roles of the interdomain interface on properties of iron centers in its hemes A and B. Isolated monoheme domains c4-A and c4-B, together with the full-length diheme c4 and its Met-to-His ligand variants, were characterized by a variety of spectroscopic and stability measurements. In both isolated domains, the heme iron is Met/His-ligated at pH 5.0, as in the full-length c4, but becomes His/His-ligated in c4-B at higher pH. Intradomain contacts in c4-A are minimally affected by the separation of c4-A and c4-B domains, and isolated c4-A is folded. In contrast, the isolated c4-B is partially unfolded, and the interface with c4-A guides folding of this domain. The c4-A and c4-B domains have the propensity to interact even without the polypeptide linker. Thermodynamic cycles have revealed properties of monomeric folded isolated domains, suggesting that ferrous (FeII), but not ferric (FeIII) c4-A and c4-B, is stabilized by the interface. This study illustrates the effects of the interface on tuning structural and redox properties of multiheme proteins and enriches our understanding of redox-dependent complexation.
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Affiliation(s)
- Fangfang Zhong
- Department of Chemistry, Dartmouth College, Hanover, NH 03755, United States
| | - Therese Albert
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR 97239, United States
| | - Pierre Moënne-Loccoz
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR 97239, United States
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Insights into the recognition and electron transfer steps in nitric oxide reductase from Marinobacter hydrocarbonoclasticus. J Inorg Biochem 2017; 177:402-411. [DOI: 10.1016/j.jinorgbio.2017.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/04/2017] [Accepted: 09/02/2017] [Indexed: 11/23/2022]
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Electron transfer and docking between cytochrome cd 1 nitrite reductase and different redox partners — A comparative study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1412-1421. [DOI: 10.1016/j.bbabio.2016.04.279] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/30/2016] [Accepted: 04/27/2016] [Indexed: 11/21/2022]
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Silveira CM, Quintas PO, Moura I, Moura JJG, Hildebrandt P, Almeida MG, Todorovic S. SERR Spectroelectrochemical Study of Cytochrome cd1 Nitrite Reductase Co-Immobilized with Physiological Redox Partner Cytochrome c552 on Biocompatible Metal Electrodes. PLoS One 2015; 10:e0129940. [PMID: 26091174 PMCID: PMC4474632 DOI: 10.1371/journal.pone.0129940] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 05/14/2015] [Indexed: 01/13/2023] Open
Abstract
Cytochrome cd1 nitrite reductases (cd1NiRs) catalyze the one-electron reduction of nitrite to nitric oxide. Due to their catalytic reaction, cd1NiRs are regarded as promising components for biosensing, bioremediation and biotechnological applications. Motivated by earlier findings that catalytic activity of cd1NiR from Marinobacter hydrocarbonoclasticus (Mhcd1) depends on the presence of its physiological redox partner, cytochrome c552 (cyt c552), we show here a detailed surface enhanced resonance Raman characterization of Mhcd1 and cyt c552 attached to biocompatible electrodes in conditions which allow direct electron transfer between the conducting support and immobilized proteins. Mhcd1 and cyt c552 are co-immobilized on silver electrodes coated with self-assembled monolayers (SAMs) and the electrocatalytic activity of Ag // SAM // Mhcd1 // cyt c552 and Ag // SAM // cyt c552 // Mhcd1 constructs is tested in the presence of nitrite. Simultaneous evaluation of structural and thermodynamic properties of the immobilized proteins reveals that cyt c552 retains its native properties, while the redox potential of apparently intact Mhcd1 undergoes a ~150 mV negative shift upon adsorption. Neither of the immobilization strategies results in an active Mhcd1, reinforcing the idea that subtle and very specific interactions between Mhcd1 and cyt c552 govern efficient intermolecular electron transfer and catalytic activity of Mhcd1.
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Affiliation(s)
- Célia M. Silveira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- * E-mail: (CMS); (ST)
| | - Pedro O. Quintas
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Isabel Moura
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - José J. G. Moura
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | | | - M. Gabriela Almeida
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
- Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Superior de Ciências da Saúde Egas Moniz, Caparica, Portugal
| | - Smilja Todorovic
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
- * E-mail: (CMS); (ST)
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Duarte AG, Cordas CM, Moura JJ, Moura I. Steady-state kinetics with nitric oxide reductase (NOR): New considerations on substrate inhibition profile and catalytic mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:375-84. [DOI: 10.1016/j.bbabio.2014.01.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 12/28/2013] [Accepted: 01/02/2014] [Indexed: 10/25/2022]
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Timóteo CG, Pereira AS, Martins CE, Naik SG, Duarte AG, Moura JJG, Tavares P, Huynh BH, Moura I. Low-spin heme b(3) in the catalytic center of nitric oxide reductase from Pseudomonas nautica. Biochemistry 2011; 50:4251-62. [PMID: 21452843 DOI: 10.1021/bi101605p] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Respiratory nitric oxide reductase (NOR) was purified from membrane extract of Pseudomonas (Ps.) nautica cells to homogeneity as judged by polyacrylamide gel electrophoresis. The purified protein is a heterodimer with subunits of molecular masses of 54 and 18 kDa. The gene encoding both subunits was cloned and sequenced. The amino acid sequence shows strong homology with enzymes of the cNOR class. Iron/heme determinations show that one heme c is present in the small subunit (NORC) and that approximately two heme b and one non-heme iron are associated with the large subunit (NORB), in agreement with the available data for enzymes of the cNOR class. Mössbauer characterization of the as-purified, ascorbate-reduced, and dithionite-reduced enzyme confirms the presence of three heme groups (the catalytic heme b(3) and the electron transfer heme b and heme c) and one redox-active non-heme Fe (Fe(B)). Consistent with results obtained for other cNORs, heme c and heme b in Ps. nautica cNOR were found to be low-spin while Fe(B) was found to be high-spin. Unexpectedly, as opposed to the presumed high-spin state for heme b(3), the Mössbauer data demonstrate unambiguously that heme b(3) is, in fact, low-spin in both ferric and ferrous states, suggesting that heme b(3) is six-coordinated regardless of its oxidation state. EPR spectroscopic measurements of the as-purified enzyme show resonances at the g ∼ 6 and g ∼ 2-3 regions very similar to those reported previously for other cNORs. The signals at g = 3.60, 2.99, 2.26, and 1.43 are attributed to the two charge-transfer low-spin ferric heme c and heme b. Previously, resonances at the g ∼ 6 region were assigned to a small quantity of uncoupled high-spin Fe(III) heme b(3). This assignment is now questionable because heme b(3) is low-spin. On the basis of our spectroscopic data, we argue that the g = 6.34 signal is likely arising from a spin-spin coupled binuclear center comprising the low-spin Fe(III) heme b(3) and the high-spin Fe(B)(III). Activity assays performed under various reducing conditions indicate that heme b(3) has to be reduced for the enzyme to be active. But, from an energetic point of view, the formation of a ferrous heme-NO as an initial reaction intermediate for NO reduction is disfavored because heme [FeNO](7) is a stable product. We suspect that the presence of a sixth ligand in the Fe(II)-heme b(3) may weaken its affinity for NO and thus promotes, in the first catalytic step, binding of NO at the Fe(B)(II) site. The function of heme b(3) would then be to orient the Fe(B)-bound NO molecules for the formation of the N-N bond and to provide reducing equivalents for NO reduction.
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Affiliation(s)
- Cristina G Timóteo
- Requimte, Centro de Química Fina e Biotecnologia, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, Monte de Caparica, Portugal
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Zheng Z, Gunner MR. Analysis of the electrochemistry of hemes with E(m)s spanning 800 mV. Proteins 2009; 75:719-34. [PMID: 19003997 DOI: 10.1002/prot.22282] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The free energy of heme reduction in different proteins is found to vary over more than 18 kcal/mol. It is a challenge to determine how proteins manage to achieve this enormous range of E(m)s with a single type of redox cofactor. Proteins containing 141 unique hemes of a-, b-, and c-type, with bis-His, His-Met, and aquo-His ligation were calculated using Multi-Conformation Continuum Electrostatics (MCCE). The experimental E(m)s range over 800 mV from -350 mV in cytochrome c(3) to 450 mV in cytochrome c peroxidase (vs. SHE). The quantitative analysis of the factors that modulate heme electrochemistry includes the interactions of the heme with its ligands, the solvent, the protein backbone, and sidechains. MCCE calculated E(m)s are in good agreement with measured values. Using no free parameters the slope of the line comparing calculated and experimental E(m)s is 0.73 (R(2) = 0.90), showing the method accounts for 73% of the observed E(m) range. Adding a +160 mV correction to the His-Met c-type hemes yields a slope of 0.97 (R(2) = 0.93). With the correction 65% of the hemes have an absolute error smaller than 60 mV and 92% are within 120 mV. The overview of heme proteins with known structures and E(m)s shows both the lowest and highest potential hemes are c-type, whereas the b-type hemes are found in the middle E(m) range. In solution, bis-His ligation lowers the E(m) by approximately 205 mV relative to hemes with His-Met ligands. The bis-His, aquo-His, and His-Met ligated b-type hemes all cluster about E(m)s which are approximately 200 mV more positive in protein than in water. In contrast, the low potential bis-His c-type hemes are shifted little from in solution, whereas the high potential His-Met c-type hemes are raised by approximately 300 mV from solution. The analysis shows that no single type of interaction can be identified as the most important in setting heme electrochemistry in proteins. For example, the loss of solvation (reaction field) energy, which raises the E(m), has been suggested to be a major factor in tuning in situ E(m)s. However, the calculated solvation energy vs. experimental E(m) shows a slope of 0.2 and R(2) of 0.5 thus correlates weakly with E(m)s. All other individual interactions show even less correlation with E(m). However the sum of these terms does reproduce the range of observed E(m)s. Therefore, different proteins use different aspects of their structures to modulate the in situ heme electrochemistry. This study also shows that the calculated E(m)s are relatively insensitive to different heme partial charges and to the protein dielectric constant used in the simulation.
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Affiliation(s)
- Zhong Zheng
- Department of Physics, The City College of New York, New York, NY, USA
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Dell’Acqua S, Pauleta SR, Monzani E, Pereira AS, Casella L, Moura JJG, Moura I. Electron Transfer Complex between Nitrous Oxide Reductase and Cytochrome c552 from Pseudomonas nautica: Kinetic, Nuclear Magnetic Resonance, and Docking Studies. Biochemistry 2008; 47:10852-62. [DOI: 10.1021/bi801375q] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Simone Dell’Acqua
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, and Dipartimento di Chimica Generale, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Sofia R. Pauleta
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, and Dipartimento di Chimica Generale, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Enrico Monzani
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, and Dipartimento di Chimica Generale, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Alice S. Pereira
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, and Dipartimento di Chimica Generale, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Luigi Casella
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, and Dipartimento di Chimica Generale, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - José J. G. Moura
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, and Dipartimento di Chimica Generale, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Isabel Moura
- REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, and Dipartimento di Chimica Generale, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
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Warren JJ, Mayer JM. Hydrogen Atom Transfer Reactions of Iron−Porphyrin−Imidazole Complexes as Models for Histidine-Ligated Heme Reactivity. J Am Chem Soc 2008; 130:2774-6. [DOI: 10.1021/ja711057t] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jeffrey J. Warren
- University of Washington, Department of Chemistry, Box 351700, Seattle, Washington 98195
| | - James M. Mayer
- University of Washington, Department of Chemistry, Box 351700, Seattle, Washington 98195
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Permina EA, Kazakov AE, Kalinina OV, Gelfand MS. Comparative genomics of regulation of heavy metal resistance in Eubacteria. BMC Microbiol 2006; 6:49. [PMID: 16753059 PMCID: PMC1526738 DOI: 10.1186/1471-2180-6-49] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2005] [Accepted: 06/05/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Heavy metal resistance (HMR) in Eubacteria is regulated by a variety of systems including transcription factors from the MerR family (COG0789). The HMR systems are characterized by the complex signal structure (strong palindrome within a 19 or 20 bp promoter spacer), and usually consist of transporter and regulator genes. Some HMR regulons also include detoxification systems. The number of sequenced bacterial genomes is constantly increasing and even though HMR resistance regulons of the COG0789 type usually consist of few genes per genome, the computational analysis may contribute to the understanding of the cellular systems of metal detoxification. RESULTS We studied the mercury (MerR), copper (CueR and HmrR), cadmium (CadR), lead (PbrR), and zinc (ZntR) resistance systems and demonstrated that combining protein sequence analysis and analysis of DNA regulatory signals it was possible to distinguish metal-dependent members of COG0789, assign specificity towards particular metals to uncharacterized loci, and find new genes involved in the metal resistance, in particular, multicopper oxidase and copper chaperones, candidate cytochromes from the copper regulon, new cadmium transporters and, possibly, glutathione-S-transferases. CONCLUSION Our data indicate that the specificity of the COG0789 systems can be determined combining phylogenetic analysis and identification of DNA regulatory sites. Taking into account signal structure, we can adequately identify genes that are activated using the DNA bending-unbending mechanism. In the case of regulon members that do not reside in single loci, analysis of potential regulatory sites could be crucial for the correct annotation and prediction of the specificity.
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Affiliation(s)
- EA Permina
- State Research Institute of Genetics and Selection of Industrial Microorganisms, 1st Dorozhnyj proezd, 1, Moscow, 113535, Russia
| | - AE Kazakov
- Institute for Information Transmission Problems, Russian Academy of Science, Bolshoi Karetny per. 19, Moscow 127994, Russia
| | - OV Kalinina
- Department of Bioengineering and Bioinformatics, Moscow State University, Laboratory Building B, Vorobiovy Gory 1-73, Moscow 119992, Russia
| | - MS Gelfand
- Institute for Information Transmission Problems, Russian Academy of Science, Bolshoi Karetny per. 19, Moscow 127994, Russia
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Electrochemical study of the intermolecular electron transfer to Pseudomonas aeruginosa cytochrome cd1 nitrite reductase. Electrochim Acta 2003. [DOI: 10.1016/s0013-4686(02)00843-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Correia dos Santos M, Paes de Sousa P, Simões Gonçalves M, Krippahl L, Moura J, Lojou É, Bianco P. Electrochemical studies on small electron transfer proteins using membrane electrodes. J Electroanal Chem (Lausanne) 2003. [DOI: 10.1016/s0022-0728(02)01427-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Alves T, Besson S, Duarte LC, Pettigrew GW, Girio FM, Devreese B, Vandenberghe I, Van Beeumen J, Fauque G, Moura I. A cytochrome c peroxidase from Pseudomonas nautica 617 active at high ionic strength: expression, purification and characterization. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1434:248-59. [PMID: 10525144 DOI: 10.1016/s0167-4838(99)00188-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cytochrome c peroxidase was expressed in cells of Pseudomonas nautica strain 617 grown under microaerophilic conditions. The 36.5 kDa dihaemic enzyme was purified to electrophoretic homogeneity in three chromatographic steps. N-terminal sequence comparison showed that the Ps. nautica enzyme exhibits a high similarity with the corresponding proteins from Paracoccus denitrificans and Pseudomonas aeruginosa. UV-visible spectra confirm calcium activation of the enzyme through spin state transition of the peroxidatic haem. Monohaemic cytochrome c(552) from Ps. nautica was identified as the physiological electron donor, with a half-saturating concentration of 122 microM and allowing a maximal catalytic centre activity of 116,000 min(-1). Using this cytochrome the enzyme retained the same activity even at high ionic strength. There are indications that the interactions between the two redox partners are mainly hydrophobic in nature.
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Affiliation(s)
- T Alves
- Departamento de Química, Centro de Tecnologia Química e Biologica, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2825-114, Caparica, Portugal
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Brown K, Nurizzo D, Besson S, Shepard W, Moura J, Moura I, Tegoni M, Cambillau C. MAD structure of Pseudomonas nautica dimeric cytochrome c552 mimicks the c4 Dihemic cytochrome domain association. J Mol Biol 1999; 289:1017-28. [PMID: 10369779 DOI: 10.1006/jmbi.1999.2838] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The monohemic cytochrome c552from Pseudomonas nautica (c552-Pn) is thought to be the electron donor to cytochrome cd1, the so-called nitrite reductase (NiR). It shows as high levels of activity and affinity for the P. nautica NiR (NiR-Pn), as the Pseudomonas aeruginosa enzyme (NiR-Pa). Since cytochrome c552is by far the most abundant electron carrier in the periplasm, it is probably involved in numerous other reactions. Its sequence is related to that of the c type cytochromes, but resembles that of the dihemic c4cytochromes even more closely. The three-dimensional structure of P. nautica cytochrome c552has been solved to 2.2 A resolution using the multiple wavelength anomalous dispersion (MAD) technique, taking advantage of the presence of the eight Fe heme ions in the asymmetric unit. Density modification procedures involving 4-fold non-crystallographic averaging yielded a model with an R -factor value of 17.8 % (Rfree=20.8 %). Cytochrome c552forms a tight dimer in the crystal, and the dimer interface area amounts to 19% of the total cytochrome surface area. Four tighly packed dimers form the eight molecules of the asymmetric unit. The c552dimer is superimposable on each domain of the monomeric cytochrome c4from Pseudomomas stutzeri (c4-Ps), a dihemic cytochrome, and on the dihemic c domain of flavocytochrome c of Chromatium vinosum (Fcd-Cv). The interacting residues which form the dimer are both similar in character and position, which is also true for the propionates. The dimer observed in the crystal also exists in solution. It has been hypothesised that the dihemic c4-Ps may have evolved via monohemic cytochrome c gene duplication followed by evolutionary divergence and the adjunction of a connecting linker. In this process, our dimeric c552structure might be said to constitute a "living fossile" occurring in the course of evolution between the formation of the dimer and the gene duplication and fusion. The availability of the structure of the cytochrome c552-Pn and that of NiR from P. aeruginosa made it possible to identify putative surface patches at which the docking of c552to NiR-Pn may occur.
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Affiliation(s)
- K Brown
- Architecture et Fonction des Macromolécules Biologiques, UP R 9039 - CNRS 31, Ch., Joseph Aiguier, Marseille Cedex 20, France
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