51
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Senge MO, MacGowan SA, O'Brien JM. Conformational control of cofactors in nature - the influence of protein-induced macrocycle distortion on the biological function of tetrapyrroles. Chem Commun (Camb) 2016; 51:17031-63. [PMID: 26482230 DOI: 10.1039/c5cc06254c] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Tetrapyrrole-containing proteins are one of the most fundamental classes of enzymes in nature and it remains an open question to give a chemical rationale for the multitude of biological reactions that can be catalyzed by these pigment-protein complexes. There are many fundamental processes where the same (i.e., chemically identical) porphyrin cofactor is involved in chemically quite distinct reactions. For example, heme is the active cofactor for oxygen transport and storage (hemoglobin, myoglobin) and for the incorporation of molecular oxygen in organic substrates (cytochrome P450). It is involved in the terminal oxidation (cytochrome c oxidase) and the metabolism of H2O2 (catalases and peroxidases) and catalyzes various electron transfer reactions in cytochromes. Likewise, in photosynthesis the same chlorophyll cofactor may function as a reaction center pigment (charge separation) or as an accessory pigment (exciton transfer) in light harvesting complexes (e.g., chlorophyll a). Whilst differences in the apoprotein sequences alone cannot explain the often drastic differences in physicochemical properties encountered for the same cofactor in diverse protein complexes, a critical factor for all biological functions must be the close structural interplay between bound cofactors and the respective apoprotein in addition to factors such as hydrogen bonding or electronic effects. Here, we explore how nature can use the same chemical molecule as a cofactor for chemically distinct reactions using the concept of conformational flexibility of tetrapyrroles. The multifaceted roles of tetrapyrroles are discussed in the context of the current knowledge on distorted porphyrins. Contemporary analytical methods now allow a more quantitative look at cofactors in protein complexes and the development of the field is illustrated by case studies on hemeproteins and photosynthetic complexes. Specific tetrapyrrole conformations are now used to prepare bioengineered designer proteins with specific catalytic or photochemical properties.
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Affiliation(s)
- Mathias O Senge
- School of Chemistry, SFI Tetrapyrrole Laboratory, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse Street, Dublin 2, Ireland and Medicinal Chemistry, Institute of Molecular Medicine, Trinity Centre for Health Sciences, Trinity College Dublin, St. James's Hospital, Dublin 8, Ireland.
| | - Stuart A MacGowan
- School of Chemistry, SFI Tetrapyrrole Laboratory, Trinity Biomedical Sciences Institute, Trinity College Dublin, The University of Dublin, 152-160 Pearse Street, Dublin 2, Ireland
| | - Jessica M O'Brien
- Medicinal Chemistry, Institute of Molecular Medicine, Trinity Centre for Health Sciences, Trinity College Dublin, St. James's Hospital, Dublin 8, Ireland.
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52
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Hosseinzadeh P, Lu Y. Design and fine-tuning redox potentials of metalloproteins involved in electron transfer in bioenergetics. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1857:557-581. [PMID: 26301482 PMCID: PMC4761536 DOI: 10.1016/j.bbabio.2015.08.006] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 08/20/2015] [Indexed: 12/25/2022]
Abstract
Redox potentials are a major contributor in controlling the electron transfer (ET) rates and thus regulating the ET processes in the bioenergetics. To maximize the efficiency of the ET process, one needs to master the art of tuning the redox potential, especially in metalloproteins, as they represent major classes of ET proteins. In this review, we first describe the importance of tuning the redox potential of ET centers and its role in regulating the ET in bioenergetic processes including photosynthesis and respiration. The main focus of this review is to summarize recent work in designing the ET centers, namely cupredoxins, cytochromes, and iron-sulfur proteins, and examples in design of protein networks involved these ET centers. We then discuss the factors that affect redox potentials of these ET centers including metal ion, the ligands to metal center and interactions beyond the primary ligand, especially non-covalent secondary coordination sphere interactions. We provide examples of strategies to fine-tune the redox potential using both natural and unnatural amino acids and native and nonnative cofactors. Several case studies are used to illustrate recent successes in this area. Outlooks for future endeavors are also provided. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson.
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Affiliation(s)
- Parisa Hosseinzadeh
- Department of Chemistry and Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews St., Urbana, IL, 61801, USA
| | - Yi Lu
- Department of Chemistry and Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews St., Urbana, IL, 61801, USA.
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53
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Morris JD, Wong KM, Peñaherrera CD, Payne CK. Mechanism of the biomolecular synthesis of PEDOT:PSS: importance of heme degradation by hydrogen peroxide. Biomater Sci 2016; 4:331-7. [DOI: 10.1039/c5bm00399g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The use of biomolecules as oxidants for the synthesis of conducting polymers provides an important tool for the control of polymer properties.
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Affiliation(s)
- J. D. Morris
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta
- USA
- Petit Institute for Bioengineering and Biosciences
| | - K. M. Wong
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta
- USA
- Petit Institute for Bioengineering and Biosciences
| | - C. D. Peñaherrera
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta
- USA
- Petit Institute for Bioengineering and Biosciences
| | - C. K. Payne
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta
- USA
- Petit Institute for Bioengineering and Biosciences
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54
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Bennett EH, Akbas N, Adrian SA, Lukat-Rodgers GS, Collins DP, Dawson JH, Allen CE, Schmitt MP, Rodgers KR, Dixon DW. Heme Binding by Corynebacterium diphtheriae HmuT: Function and Heme Environment. Biochemistry 2015; 54:6598-609. [PMID: 26478504 PMCID: PMC4943319 DOI: 10.1021/acs.biochem.5b00666] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The heme uptake pathway (hmu) of Corynebacterium diphtheriae utilizes multiple proteins to bind and transport heme into the cell. One of these proteins, HmuT, delivers heme to the ABC transporter HmuUV. In this study, the axial ligation of the heme in ferric HmuT is probed by examination of wild-type (WT) HmuT and a series of conserved heme pocket residue mutants, H136A, Y235A, and M292A. Characterization by UV-visible, resonance Raman, and magnetic circular dichroism spectroscopies indicates that H136 and Y235 are the axial ligands in ferric HmuT. Consistent with this assignment of axial ligands, ferric WT and H136A HmuT are difficult to reduce while Y235A is reduced readily in the presence of dithionite. The FeCO Raman shifts in WT, H136A, and Y235A HmuT-CO complexes provide further evidence of the axial ligand assignments. Additionally, these frequencies provide insight into the nonbonding environment of the heme pocket. Ferrous Y235A and the Y235A-CO complex reveal that the imidazole of H136 exists in two forms, one neutral and one with imidazolate character, consistent with a hydrogen bond acceptor on the H136 side of the heme. The ferric fluoride complex of Y235A reveals the presence of at least one hydrogen bond donor on the Y235 side of the heme. Hemoglobin utilization assays showed that the axial Y235 ligand is required for heme uptake in HmuT.
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Affiliation(s)
| | - Neval Akbas
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302-3965
| | - Seth A. Adrian
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050
| | - Gudrun S. Lukat-Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050
| | - Daniel P. Collins
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - John H. Dawson
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Courtni E. Allen
- Laboratory of Respiratory and Special Pathogens, Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation, and Research, Food and Drug Administration, Silver Spring, Maryland 20993
| | - Michael P. Schmitt
- Laboratory of Respiratory and Special Pathogens, Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation, and Research, Food and Drug Administration, Silver Spring, Maryland 20993
| | - Kenton R. Rodgers
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050
| | - Dabney W. Dixon
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302-3965
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55
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Kunkel SA, Pagilla KR, Stark BC. Directed evolution to produce sludge communities with improved oxygen uptake abilities. Appl Microbiol Biotechnol 2015; 99:10725-34. [PMID: 26278534 DOI: 10.1007/s00253-015-6891-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/23/2015] [Accepted: 07/28/2015] [Indexed: 11/30/2022]
Abstract
Two activated sludge cultures, seeded with activated sludge from the same source, were cultivated for 370 days in synthetic wastewater. Both cultures were transferred weekly to fresh medium; one culture was operated at high dissolved oxygen (DO) (near saturation) and the other at low DO (0.25 mg O2/L). There were significant changes in the abundances of bacterial species and phyla present in each culture throughout the 370-day operational period. In the low DO culture, over time, there was a continuously increasing proportion of cells of species known to encode truncated hemoglobins (Hbs). These are the types of Hbs which may enhance delivery of oxygen to the respiratory chain, to enhance ATP production, especially under low aeration conditions. The levels of heme b, the heme found in Vitreoscilla hemoglobin, increased in parallel to the increase in Hb-encoding species, to much higher levels in the low DO culture than in the high DO culture. Specific oxygen uptake rates increased by 3 % for the high DO culture near the end of the 370-day period, while those for the low DO culture increased steadily to a level 28 % higher than that of the starting culture. Thus, imposition of low DO conditions may, due to selection for Hb-expressing species, be useful in developing bacterial communities with enhanced ability to function efficiently in aerobic wastewater treatment, especially under low aeration conditions.
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Affiliation(s)
- Stephanie A Kunkel
- Department of Biology, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Krishna R Pagilla
- Department of Civil, Architectural and Environmental Engineering, Illinois Institute of Technology, Chicago, IL, 60616, USA
| | - Benjamin C Stark
- Department of Biology, Illinois Institute of Technology, Chicago, IL, 60616, USA.
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56
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Kleingardner JG, Bren KL. Biological significance and applications of heme c proteins and peptides. Acc Chem Res 2015; 48:1845-52. [PMID: 26083801 DOI: 10.1021/acs.accounts.5b00106] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Hemes are ubiquitous in biology and carry out a wide range of functions. The heme group is largely invariant across proteins with different functions, although there are a few variations seen in nature. The most common variant is heme c, which is formed by a post-translational modification in which heme is covalently linked to two Cys residues on the polypeptide via thioether bonds. In this Account, the influence of this covalent attachment on heme c properties and function is discussed, and examples of how covalent attachment has been used in selected applications are presented. Proteins that bind heme c are among the most well-characterized proteins in biochemistry. Most of these proteins are cytochromes c (cyts c) that serve as electron carriers in photosynthesis and respiration. Despite the intense study of cyts c, the functional significance of heme covalent attachment has remained elusive. One observation is that heme c reaches a lower reduction potential in nature than its noncovalently linked counterpart, heme b, when comparing proteins with the same axial ligands. Furthermore, covalent attachment is known to enhance protein stability and allow the heme to be relatively solvent exposed. However, an inorganic chemistry perspective on the effects of covalent attachment has been lacking. Spectroscopic measurements and computations on cyts c and model systems reveal a number of effects of covalent attachment on heme electronic structure and reactivity. One is that the predominant nonplanar ruffling distortion seen in heme c lowers heme reduction potential. Another is that covalent attachment influences the interaction of the heme iron with the proximal His ligand. Heme ruffling also has been shown to influence electronic coupling to redox partners and, therefore, electron transfer rates by altering the distribution of the orbital hole on the porphyrin in oxidized cyt c. Another consequence of heme covalent attachment is the strong vibrational coupling seen between the iron and the protein surface as revealed by nuclear resonance vibrational spectroscopy studies. Finally, heme covalent attachment is proposed to be an important feature supporting multiple roles of cyt c in programmed cell death (apoptosis). Heme covalent attachment is not only vital for the biological functions of cyt c but also provides a useful handle in a number of applications. For one, the engineering of heme c onto an exposed portion of a protein of interest has been shown to provide a visible affinity purification tag. In addition, peptides with covalently attached heme, known as microperoxidases, have been studied as model compounds and oxidation catalysts and, more recently, in applications for energy conversion and storage. The wealth of insight gained about heme c through fundamental studies of cyts c forms a basis for future efforts toward engineering natural and artificial cytochromes for a variety of applications.
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Affiliation(s)
- Jesse G. Kleingardner
- Department
of Chemistry, Ithaca College, Ithaca, New York 14850, United States
- Department
of Chemistry, University of Rochester, Rochester, New York 14618, United States
| | - Kara L. Bren
- Department
of Chemistry, University of Rochester, Rochester, New York 14618, United States
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57
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Dantas JM, Campelo LM, Duke NEC, Salgueiro CA, Pokkuluri PR. The structure of PccH from Geobacter sulfurreducens - a novel low reduction potential monoheme cytochrome essential for accepting electrons from an electrode. FEBS J 2015; 282:2215-31. [PMID: 25786707 DOI: 10.1111/febs.13269] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 02/09/2015] [Accepted: 03/13/2015] [Indexed: 11/27/2022]
Abstract
The structure of cytochrome c (GSU3274) designated as PccH from Geobacter sulfurreducens was determined at a resolution of 2.0 Å. PccH is a small (15 kDa) cytochrome containing one c-type heme, found to be essential for the growth of G. sulfurreducens with respect to accepting electrons from graphite electrodes poised at -300 mV versus standard hydrogen electrode. with fumarate as the terminal electron acceptor. The structure of PccH is unique among the monoheme cytochromes described to date. The structural fold of PccH can be described as forming two lobes with the heme sandwiched in a cleft between the two lobes. In addition, PccH has a low reduction potential of -24 mV at pH 7, which is unusual for monoheme cytochromes. Based on difference in structure, together with sequence phylogenetic analysis, we propose that PccH can be regarded as a first characterized example of a new subclass of class I monoheme cytochromes. The low reduction potential of PccH may enable the protein to be redox active at the typically negative potential ranges encountered by G. sulfurreducens. Because PccH is predicted to be located in the periplasm of this bacterium, it could not be involved in the first step of accepting electrons from the electrode but is very likely involved in the downstream electron transport events in the periplasm.
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Affiliation(s)
- Joana M Dantas
- UCIBIO - REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Luísa M Campelo
- UCIBIO - REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - Norma E C Duke
- Biosciences Division, Argonne National Laboratory, Lemont, IL, USA
| | - Carlos A Salgueiro
- UCIBIO - REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
| | - P Raj Pokkuluri
- Biosciences Division, Argonne National Laboratory, Lemont, IL, USA
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58
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Levitt DG, Levitt MD. Carbon monoxide: a critical quantitative analysis and review of the extent and limitations of its second messenger function. Clin Pharmacol 2015; 7:37-56. [PMID: 25750547 PMCID: PMC4348054 DOI: 10.2147/cpaa.s79626] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Endogenously produced carbon monoxide (CO) is commonly believed to be a ubiquitous second messenger involved in a wide range of physiological and pathological responses. The major evidence supporting this concept is that CO is produced endogenously via heme oxygenase-catalyzed breakdown of heme and that experimental exposure to CO alters tissue function. However, it remains to be conclusively demonstrated that there are specific receptors for CO and that endogenous CO production is sufficient to alter tissue function. Unlike other signaling molecules, CO is not significantly metabolized, and it is removed from cells solely via rapid diffusion into blood, which serves as a near infinite sink. This non-metabolizable nature of CO renders the physiology of this gas uniquely susceptible to quantitative modeling. This review analyzes each of the steps involved in CO signaling: 1) the background CO partial pressure (PCO) and the blood and tissue CO binding; 2) the affinity of the putative CO receptors; 3) the rate of endogenous tissue CO production; and 4) the tissue PCO that results from the balance between this endogenous CO production and diffusion to the blood sink. Because existing data demonstrate that virtually all endogenous CO production results from the routine "housekeeping" turnover of heme, only a small fraction can play a signaling role. The novel aspect of the present report is to demonstrate via physiological modeling that this small fraction of CO production is seemingly insufficient to raise intracellular PCO to the levels required for the conventional, specific messenger receptor activation. It is concluded that the many physiological alterations observed with exogenous CO administration are probably produced by the non-specific CO inhibition of cytochrome C oxidase activity, with release of reactive oxygen species (ROS) and that this ROS signaling pathway is a potential effector mechanism for endogenously produced CO.
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Affiliation(s)
- David G Levitt
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Michael D Levitt
- Research Service, Veterans Affairs Medical Center, Minneapolis, MN, USA
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59
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Brito JA, Denkmann K, Pereira IAC, Archer M, Dahl C. Thiosulfate dehydrogenase (TsdA) from Allochromatium vinosum: structural and functional insights into thiosulfate oxidation. J Biol Chem 2015; 290:9222-38. [PMID: 25673691 DOI: 10.1074/jbc.m114.623397] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Indexed: 11/06/2022] Open
Abstract
Although the oxidative condensation of two thiosulfate anions to tetrathionate constitutes a well documented and significant part of the natural sulfur cycle, little is known about the enzymes catalyzing this reaction. In the purple sulfur bacterium Allochromatium vinosum, the reaction is catalyzed by the periplasmic diheme c-type cytochrome thiosulfate dehydrogenase (TsdA). Here, we report the crystal structure of the "as isolated" form of A. vinosum TsdA to 1.98 Å resolution and those of several redox states of the enzyme to different resolutions. The protein contains two typical class I c-type cytochrome domains wrapped around two hemes axially coordinated by His(53)/Cys(96) and His(164)/Lys(208). These domains are very similar, suggesting a gene duplication event during evolution. A ligand switch from Lys(208) to Met(209) is observed upon reduction of the enzyme. Cys(96) is an essential residue for catalysis, with the specific activity of the enzyme being completely abolished in several TsdA-Cys(96) variants. TsdA-K208N, K208G, and M209G variants were catalytically active in thiosulfate oxidation as well as in tetrathionate reduction, pointing to heme 2 as the electron exit point. In this study, we provide spectroscopic and structural evidence that the TsdA reaction cycle involves the transient presence of heme 1 in the high-spin state caused by movement of the Sγ atom of Cys(96) out of the iron coordination sphere. Based on the presented data, we draw important conclusions about the enzyme and propose a possible reaction mechanism for TsdA.
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Affiliation(s)
- José A Brito
- From the Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB-UNL), Avenida da República, 2780-157 Oeiras, Portugal and
| | - Kevin Denkmann
- the Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, D-53115 Bonn, Germany
| | - Inês A C Pereira
- From the Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB-UNL), Avenida da República, 2780-157 Oeiras, Portugal and
| | - Margarida Archer
- From the Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB-UNL), Avenida da República, 2780-157 Oeiras, Portugal and
| | - Christiane Dahl
- the Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, D-53115 Bonn, Germany
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60
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Morris JD, Khanal D, Richey JA, Payne CK. Hemoglobin-mediated synthesis of PEDOT:PSS: enhancing conductivity through biological oxidants. Biomater Sci 2015. [DOI: 10.1039/c4bm00338a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hemoglobin is used as an oxidant to generate highly conductive PEDOT:PSS with bipolarons, while catalase generates a less conductive polymer that possesses polarons.
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Affiliation(s)
- J. D. Morris
- School of Science and Technology
- Georgia Gwinnett College
- Lawrenceville
- USA
| | - D. Khanal
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta
- USA
- Petit Institute for Bioengineering and Biosciences
| | - J. A. Richey
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta
- USA
- Petit Institute for Bioengineering and Biosciences
| | - C. K. Payne
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta
- USA
- Petit Institute for Bioengineering and Biosciences
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61
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Aledo JC, Valverde H, Ruíz-Camacho M, Morilla I, López FD. Protein-protein interfaces from cytochrome c oxidase I evolve faster than nonbinding surfaces, yet negative selection is the driving force. Genome Biol Evol 2014; 6:3064-76. [PMID: 25359921 PMCID: PMC4255772 DOI: 10.1093/gbe/evu240] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Respiratory complexes are encoded by two genomes (mitochondrial DNA [mtDNA] and nuclear DNA [nDNA]). Although the importance of intergenomic coadaptation is acknowledged, the forces and constraints shaping such coevolution are largely unknown. Previous works using cytochrome c oxidase (COX) as a model enzyme have led to the so-called “optimizing interaction” hypothesis. According to this view, mtDNA-encoded residues close to nDNA-encoded residues evolve faster than the rest of positions, favoring the optimization of protein–protein interfaces. Herein, using evolutionary data in combination with structural information of COX, we show that failing to discern the effects of interaction from other structural and functional effects can lead to deceptive conclusions such as the “optimizing hypothesis.” Once spurious factors have been accounted for, data analysis shows that mtDNA-encoded residues engaged in contacts are, in general, more constrained than their noncontact counterparts. Nevertheless, noncontact residues from the surface of COX I subunit are a remarkable exception, being subjected to an exceptionally high purifying selection that may be related to the maintenance of a suitable heme environment. We also report that mtDNA-encoded residues involved in contacts with other mtDNA-encoded subunits are more constrained than mtDNA-encoded residues interacting with nDNA-encoded polypeptides. This differential behavior cannot be explained on the basis of predicted thermodynamic stability, as interactions between mtDNA-encoded subunits contribute more weakly to the complex stability than those interactions between subunits encoded by different genomes. Therefore, the higher conservation observed among mtDNA-encoded residues involved in intragenome interactions is likely due to factors other than structural stability.
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Affiliation(s)
- Juan Carlos Aledo
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Spain
| | - Héctor Valverde
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Spain
| | - Manuel Ruíz-Camacho
- Departamento de Estadística e Investigación Operativa, Facultad de Ciencias, Universidad de Málaga, Spain
| | - Ian Morilla
- Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, Spain
| | - Francisco Demetrio López
- Departamento de Estadística e Investigación Operativa, Facultad de Ciencias, Universidad de Málaga, Spain
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62
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Bhagi-Damodaran A, Petrik ID, Marshall NM, Robinson H, Lu Y. Systematic tuning of heme redox potentials and its effects on O2 reduction rates in a designed oxidase in myoglobin. J Am Chem Soc 2014; 136:11882-5. [PMID: 25076049 PMCID: PMC4151708 DOI: 10.1021/ja5054863] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Indexed: 11/28/2022]
Abstract
Cytochrome c Oxidase (CcO) is known to catalyze the reduction of O2 to H2O efficiently with a much lower overpotential than most other O2 reduction catalysts. However, methods by which the enzyme fine-tunes the reduction potential (E°) of its active site and the corresponding influence on the O2 reduction activity are not well understood. In this work, we report systematic tuning of the heme E° in a functional model of CcO in myoglobin containing three histidines and one tyrosine in the distal pocket of heme. By removing hydrogen-bonding interactions between Ser92 and the proximal His ligand and a heme propionate, and increasing hydrophobicity of the heme pocket through Ser92Ala mutation, we have increased the heme E° from 95 ± 2 to 123 ± 3 mV. Additionally, replacing the native heme b in the CcO mimic with heme a analogs, diacetyl, monoformyl, and diformyl hemes, that posses electron-withdrawing groups, resulted in higher E° values of 175 ± 5, 210 ± 6, and 320 ± 10 mV, respectively. Furthermore, O2 consumption studies on these CcO mimics revealed a strong enhancement in O2 reduction rates with increasing heme E°. Such methods of tuning the heme E° through a combination of secondary sphere mutations and heme substitutions can be applied to tune E° of other heme proteins, allowing for comprehensive investigations of the relationship between E° and enzymatic activity.
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Affiliation(s)
- Ambika Bhagi-Damodaran
- Department
of Chemistry, University of Illinois, Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Igor D. Petrik
- Department
of Chemistry, University of Illinois, Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Nicholas M. Marshall
- Department
of Chemistry, University of Illinois, Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Howard Robinson
- Department
of Biology, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Yi Lu
- Department
of Chemistry, University of Illinois, Urbana−Champaign, Urbana, Illinois 61801, United States
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63
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Molecular mechanisms of heme based sensors from sediment organisms capable of extracellular electron transfer. J Inorg Biochem 2014; 133:104-9. [DOI: 10.1016/j.jinorgbio.2013.10.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/15/2013] [Accepted: 10/23/2013] [Indexed: 11/18/2022]
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64
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Shin S, Davidson VL. MauG, a diheme enzyme that catalyzes tryptophan tryptophylquinone biosynthesis by remote catalysis. Arch Biochem Biophys 2014; 544:112-8. [PMID: 24144526 PMCID: PMC3946517 DOI: 10.1016/j.abb.2013.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 10/03/2013] [Accepted: 10/08/2013] [Indexed: 11/30/2022]
Abstract
MauG contains two c-type hemes with atypical physical and catalytic properties. While most c-type cytochromes function simply as electron transfer mediators, MauG catalyzes the completion of tryptophan tryptophylquinone (TTQ)(1) biosynthesis within a precursor protein of methylamine dehydrogenase. This posttranslational modification is a six-electron oxidation that requires crosslinking of two Trp residues, oxygenation of a Trp residue and oxidation of the resulting quinol to TTQ. These reactions proceed via a bis-Fe(IV) state in which one heme is present as Fe(IV)O and the other is Fe(IV) with axial heme ligands provided by His and Tyr side chains. Catalysis does not involve direct contact between the protein substrate and either heme of MauG. Instead it is accomplished by remote catalysis using a hole hopping mechanism of electron transfer in which Trp residues of MauG are reversibly oxidized. In this process, long range electron transfer is coupled to the radical mediated chemical reactions that are required for TTQ biosynthesis.
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Affiliation(s)
- Sooim Shin
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA
| | - Victor L Davidson
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA.
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65
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Bird LJ, Saraiva IH, Park S, Calçada EO, Salgueiro CA, Nitschke W, Louro RO, Newman DK. Nonredundant roles for cytochrome c2 and two high-potential iron-sulfur proteins in the photoferrotroph Rhodopseudomonas palustris TIE-1. J Bacteriol 2014; 196:850-8. [PMID: 24317397 PMCID: PMC3911180 DOI: 10.1128/jb.00843-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 11/28/2013] [Indexed: 11/20/2022] Open
Abstract
The purple bacterium Rhodopseudomonas palustris TIE-1 expresses multiple small high-potential redox proteins during photoautotrophic growth, including two high-potential iron-sulfur proteins (HiPIPs) (PioC and Rpal_4085) and a cytochrome c2. We evaluated the role of these proteins in TIE-1 through genetic, physiological, and biochemical analyses. Deleting the gene encoding cytochrome c2 resulted in a loss of photosynthetic ability by TIE-1, indicating that this protein cannot be replaced by either HiPIP in cyclic electron flow. PioC was previously implicated in photoferrotrophy, an unusual form of photosynthesis in which reducing power is provided through ferrous iron oxidation. Using cyclic voltammetry (CV), electron paramagnetic resonance (EPR) spectroscopy, and flash-induced spectrometry, we show that PioC has a midpoint potential of 450 mV, contains all the typical features of a HiPIP, and can reduce the reaction centers of membrane suspensions in a light-dependent manner at a much lower rate than cytochrome c2. These data support the hypothesis that PioC linearly transfers electrons from iron, while cytochrome c2 is required for cyclic electron flow. Rpal_4085, despite having spectroscopic characteristics and a reduction potential similar to those of PioC, is unable to reduce the reaction center. Rpal_4085 is upregulated by the divalent metals Fe(II), Ni(II), and Co(II), suggesting that it might play a role in sensing or oxidizing metals in the periplasm. Taken together, our results suggest that these three small electron transfer proteins perform different functions in the cell.
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Affiliation(s)
- Lina J. Bird
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Divisions of Biology and Geological and Planetary Sciences, Howard Hughes Medical Institute at the California Institute of Technology, Pasadena, California, USA
| | - Ivo H. Saraiva
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Shannon Park
- Divisions of Biology and Geological and Planetary Sciences, Howard Hughes Medical Institute at the California Institute of Technology, Pasadena, California, USA
| | - Eduardo O. Calçada
- Requimte, CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Monte da Caparica, Portugal
| | - Carlos A. Salgueiro
- Requimte, CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Monte da Caparica, Portugal
| | - Wolfgang Nitschke
- Laboratoire de Bioénergétique et Ingénierie des Protéines (UMR7281), CNRS/AMU, FR3479, Marseille, France
| | - Ricardo O. Louro
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Dianne K. Newman
- Divisions of Biology and Geological and Planetary Sciences, Howard Hughes Medical Institute at the California Institute of Technology, Pasadena, California, USA
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66
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Tehrani HS, Moosavi-Movahedi A, Ghourchian H. Correlation between biological activity and electron transferring of bovine liver catalase: Osmolytes effects. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.09.100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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67
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Martínez-Sernández V, Mezo M, González-Warleta M, Perteguer MJ, Muiño L, Guitián E, Gárate T, Ubeira FM. The MF6p/FhHDM-1 major antigen secreted by the trematode parasite Fasciola hepatica is a heme-binding protein. J Biol Chem 2013; 289:1441-56. [PMID: 24280214 DOI: 10.1074/jbc.m113.499517] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Blood-feeding parasites have developed biochemical mechanisms to control heme intake and detoxification. Here we show that a major antigen secreted by Fasciola hepatica, previously reported as MF6p, of unknown function (gb|CCA61804.1), and as FhHDM-1, considered to be a helminth defense molecule belonging to the family of cathelicidin-like proteins (gb|ADZ24001.1), is in fact a heme-binding protein. The heme-binding nature of the MF6p/FhHDM-1 protein was revealed in two independent experiments: (i) immunopurification of the secreted protein·heme complexes with mAb MF6 and subsequent analysis by C8 reversed-phase HPLC and MS/MS spectrometry and (ii) analysis of the binding ability of the synthetic protein to hemin in vitro. By immunohistochemistry analysis, we have observed that MF6p/FhHDM-1 is produced by parenchymal cells and transported to other tissues (e.g. vitellaria and testis). Interestingly, MF6p/FhHDM-1 is absent both in the intestinal cells and in the lumen of cecum, but it can be released through the tegumental surface to the external medium, where it binds to free heme molecules regurgitated by the parasite after hemoglobin digestion. Proteins that are close analogs of the Fasciola MF6p/FhHDM-1 are present in other trematodes, including Clonorchis, Opistorchis, Paragonimus, Schistosoma, and Dicrocoelium. Using UV-visible spectroscopy and immunoprecipitation techniques, we observed that synthetic MF6p/FhHDM-1 binds to hemin with 1:1 stoichiometry and an apparent Kd of 1.14 × 10(-6) M(-1). We also demonstrated that formation of synthetic MF6p/FhHDM-1·hemin complexes inhibited hemin degradation by hydrogen peroxide and hemin peroxidase-like activity in vitro. Our results suggest that MF6p/FhHDM-1 may be involved in heme homeostasis in trematodes.
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Affiliation(s)
- Victoria Martínez-Sernández
- From the Laboratorio de Parasitología, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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68
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Liu J, Dong Y, Zheng J, He Y, Sheng Q. Investigation on the conformation change of hemoglobin immobilized on MPA-modified electrode by electrochemical method. ANAL SCI 2013; 29:1075-81. [PMID: 24212734 DOI: 10.2116/analsci.29.1075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The conformation change of bovine hemoglobin (Hb) during the unfolding process induced by urea and acid was investigated by an electrochemical method. Hb unfolding induced by urea of different concentrations was realized by bonding Hb onto a 3-mercaptopropionic acid (MPA) modified gold electrode. The difference in unfolding percentage showed that the Hb unfolding induced by urea was a two-step, three-state transition process, while the unfolding induced by acid was a two-state transition process. The results obtained by the electrochemical method coincided closely with those obtained by UV-vis spectroscopy and fluorescence spectroscopy. Some thermodynamic parameters during the conformational change were also calculated to study the intermediate state during the Hb unfolding process. The present work may lead to an easy and effective way to study metalloproteins unfolding, and holds great promise for the design of novel sensitive biosensors.
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Affiliation(s)
- Jianbo Liu
- Institute of Analytical Science/Shaanxi Provincial Key Laboratory of Electroanalytical Chemistry, Northwest University
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69
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Coelho PS, Wang ZJ, Ener ME, Baril SA, Kannan AA, Arnold FH, Brustad EM. A serine-substituted P450 catalyzes highly efficient carbene transfer to olefins in vivo. Nat Chem Biol 2013; 9:485-7. [PMID: 23792734 PMCID: PMC3720782 DOI: 10.1038/nchembio.1278] [Citation(s) in RCA: 243] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 05/17/2013] [Indexed: 11/09/2022]
Abstract
Whole-cell catalysts for non-natural chemical reactions will open new routes to sustainable production of chemicals. We designed a cytochrome 'P411' with unique serine-heme ligation that catalyzes efficient and selective olefin cyclopropanation in intact Escherichia coli cells. The mutation C400S in cytochrome P450(BM3) gives a signature ferrous CO Soret peak at 411 nm, abolishes monooxygenation activity, raises the resting-state Fe(III)-to-Fe(II) reduction potential and substantially improves NAD(P)H-driven activity.
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Affiliation(s)
- Pedro S. Coelho
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Z. Jane Wang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Maraia E. Ener
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Stefanie A. Baril
- Department of Chemistry and Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Arvind A. Kannan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Frances H. Arnold
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Eric M. Brustad
- Department of Chemistry and Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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70
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Can M, Krucinska J, Zoppellaro G, Andersen NH, Wedekind JE, Hersleth HP, Andersson KK, Bren KL. Structural characterization of nitrosomonas europaea cytochrome c-552 variants with marked differences in electronic structure. Chembiochem 2013; 14:1828-38. [PMID: 23908017 DOI: 10.1002/cbic.201300118] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Indexed: 11/09/2022]
Abstract
Nitrosomonas europaea cytochrome c-552 (Ne c-552) variants with the same His/Met axial ligand set but with different EPR spectra have been characterized structurally, to aid understanding of how molecular structure determines heme electronic structure. Visible light absorption, Raman, and resonance Raman spectroscopy of the protein crystals was performed along with structure determination. The structures solved are those of Ne c-552, which displays a "HALS" (or highly anisotropic low-spin) EPR spectrum, and of the deletion mutant Ne N64Δ, which has a rhombic EPR spectrum. Two X-ray crystal structures of wild-type Ne c-552 are reported; one is of the protein isolated from N. europaea cells (Ne c-552n, 2.35 Å resolution), and the other is of recombinant protein expressed in Escherichia coli (Ne c-552r, 1.63 Å resolution). Ne N64Δ crystallized in two different space groups, and two structures are reported [monoclinic (2.1 Å resolution) and hexagonal (2.3 Å resolution)]. Comparison of the structures of the wild-type and mutant proteins reveals that heme ruffling is increased in the mutant; increased ruffling is predicted to yield a more rhombic EPR spectrum. The 2.35 Å Ne c-552n structure shows 18 molecules in the asymmetric unit; analysis of the structure is consistent with population of more than one axial Met configuration, as seen previously by NMR. Finally, the mutation was shown to yield a more hydrophobic heme pocket and to expel water molecules from near the axial Met. These structures reveal that heme pocket residue 64 plays multiple roles in regulating the axial ligand orientation and the interaction of water with the heme. These results support the hypothesis that more ruffled hemes lead to more rhombic EPR signals in cytochromes c with His/Met axial ligation.
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Affiliation(s)
- Mehmet Can
- Department of Chemistry, University of Rochester, Rochester, NY 14627 (USA)
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71
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Yin L, Bauer CE. Controlling the delicate balance of tetrapyrrole biosynthesis. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120262. [PMID: 23754814 DOI: 10.1098/rstb.2012.0262] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tetrapyrroles are a family of compounds that contain four pyrrole rings. They are involved in many fundamental biological processes such as photoreception, electron transport, gas transport and also as cofactors for enzymatic reactions. As regulators of protein activity, tetrapyrroles mediate cellular response to light, oxygen and nutrient levels in the surrounding environment. Biosynthesis of haem tetrapyrroles shares, conserved pathways and enzymes among all three domains of life. This is contrasted by chlorophyll biosynthesis that is only present in eubacteria and chloroplasts, or cobalamin biosynthesis that is only present in eubacteria and archaea. This implicates haem as the most ancient, and chlorophyll as the most recent, of the common tetrapyrroles that are currently synthesized by existing organisms. Haem and chlorophyll are both toxic when synthesized in excess over apo-proteins that bind these tetrapyrroles. Accordingly, the synthesis of these tetrapyrroles has to be tightly regulated and coordinated with apo-protein production. The mechanism of regulating haem and chlorophyll synthesis has been studied intensively in Rhodobacter species and will be discussed.
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Affiliation(s)
- Liang Yin
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
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72
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Della Pia EA, Chi Q, Elliott M, Macdonald JE, Ulstrup J, Jones DD. Redox tuning of cytochrome b562 through facile metal porphyrin substitution. Chem Commun (Camb) 2013; 48:10624-6. [PMID: 22992595 DOI: 10.1039/c2cc34302a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The biologically and nanotechnologically important heme protein cytochrome b(562) was reconstructed with zinc and copper porphyrins, leading to significant changes in the spectral, redox and electron transfer properties. The Cu form shifts the redox potential by +300 mV and exhibits high electron transfer, while the Zn form is redox inert.
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73
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MacGowan SA, Senge MO. Computational Quantification of the Physicochemical Effects of Heme Distortion: Redox Control in the Reaction Center Cytochrome Subunit of Blastochloris viridis. Inorg Chem 2013; 52:1228-37. [DOI: 10.1021/ic301530t] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stuart A. MacGowan
- School of Chemistry, SFI Tetrapyrrole
Laboratory, Trinity Biomedical Sciences Institute, 152-160 Pearse
Street, Trinity College Dublin, Dublin
2, Ireland
| | - Mathias O. Senge
- School of Chemistry, SFI Tetrapyrrole
Laboratory, Trinity Biomedical Sciences Institute, 152-160 Pearse
Street, Trinity College Dublin, Dublin
2, Ireland
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74
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Tallack MR, Magor GW, Dartigues B, Sun L, Huang S, Fittock JM, Fry SV, Glazov EA, Bailey TL, Perkins AC. Novel roles for KLF1 in erythropoiesis revealed by mRNA-seq. Genome Res 2012; 22:2385-98. [PMID: 22835905 PMCID: PMC3514668 DOI: 10.1101/gr.135707.111] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
KLF1 (formerly known as EKLF) regulates the development of erythroid cells from bi-potent progenitor cells via the transcriptional activation of a diverse set of genes. Mice lacking Klf1 die in utero prior to E15 from severe anemia due to the inadequate expression of genes controlling hemoglobin production, cell membrane and cytoskeletal integrity, and the cell cycle. We have recently described the full repertoire of KLF1 binding sites in vivo by performing KLF1 ChIP-seq in primary erythroid tissue (E14.5 fetal liver). Here we describe the KLF1-dependent erythroid transcriptome by comparing mRNA-seq from Klf1+/+ and Klf1−/− erythroid tissue. This has revealed novel target genes not previously obtainable by traditional microarray technology, and provided novel insights into the function of KLF1 as a transcriptional activator. We define a cis-regulatory module bound by KLF1, GATA1, TAL1, and EP300 that coordinates a core set of erythroid genes. We also describe a novel set of erythroid-specific promoters that drive high-level expression of otherwise ubiquitously expressed genes in erythroid cells. Our study has identified two novel lncRNAs that are dynamically expressed during erythroid differentiation, and discovered a role for KLF1 in directing apoptotic gene expression to drive the terminal stages of erythroid maturation.
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Affiliation(s)
- Michael R Tallack
- Mater Medical Research Institute, Mater Hospital, Brisbane, Queensland 4101, Australia
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75
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Saraiva IH, Newman DK, Louro RO. Functional characterization of the FoxE iron oxidoreductase from the photoferrotroph Rhodobacter ferrooxidans SW2. J Biol Chem 2012; 287:25541-8. [PMID: 22661703 DOI: 10.1074/jbc.m112.360636] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Photoferrotrophy is presumed to be an ancient type of photosynthetic metabolism in which bacteria use the reducing power of ferrous iron to drive carbon fixation. In this work the putative iron oxidoreductase of the photoferrotroph Rhodobacter ferrooxidans SW2 was cloned, purified, and characterized for the first time. This protein, FoxE, was characterized using spectroscopic, thermodynamic, and kinetic techniques. It is a c-type cytochrome that forms a trimer or tetramer in solution; the two hemes of each monomer are hexacoordinated by histidine and methionine. The hemes have positive reduction potentials that allow downhill electron transfer from many geochemically relevant ferrous iron forms to the photosynthetic reaction center. The reduction potentials of the hemes are different and are cross-assigned to fast and slow kinetic phases of ferrous iron oxidation in vitro. Lower reactivity was observed at high pH and may contribute to prevent ferric iron precipitation inside or at the surface of the cell. These results help fill in the molecular details of a metabolic process that likely contributed to the deposition of precambrian banded iron formations, globally important sedimentary rocks that are found on every continent today.
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Affiliation(s)
- Ivo H Saraiva
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
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76
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Yin L, Dragnea V, Bauer CE. PpsR, a regulator of heme and bacteriochlorophyll biosynthesis, is a heme-sensing protein. J Biol Chem 2012; 287:13850-8. [PMID: 22378778 DOI: 10.1074/jbc.m112.346494] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heme-mediated regulation, presented in many biological processes, is achieved in part with proteins containing heme regulatory motif. In this study, we demonstrate that FLAG-tagged PpsR isolated from Rhodobacter sphaeroides cells contains bound heme. In vitro heme binding studies with tagless apo-PpsR show that PpsR binds heme at a near one-to-one ratio with a micromolar binding constant. Mutational and spectral assays suggest that both the second Per-Arnt-Sim (PAS) and DNA binding domains of PpsR are involved in the heme binding. Furthermore, we show that heme changes the DNA binding patterns of PpsR and induces different responses of photosystem genes expression. Thus, PpsR functions as both a redox and heme sensor to coordinate the amount of heme, bacteriochlorophyll, and photosystem apoprotein synthesis thereby providing fine tune control to avoid excess free tetrapyrrole accumulation.
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Affiliation(s)
- Liang Yin
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, USA
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77
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Shinde S, Cordova JM, Woodrum BW, Ghirlanda G. Modulation of function in a minimalist heme-binding membrane protein. J Biol Inorg Chem 2012; 17:557-64. [PMID: 22307279 DOI: 10.1007/s00775-012-0876-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 01/14/2012] [Indexed: 12/21/2022]
Abstract
De novo designed heme-binding proteins have been used successfully to recapitulate features of natural hemoproteins. This approach has now been extended to membrane-soluble model proteins. Our group designed a functional hemoprotein, ME1, by engineering a bishistidine binding site into a natural membrane protein, glycophorin A (Cordova et al. in J Am Chem Soc 129:512-518, 2007). ME1 binds iron(III) protoporphyrin IX with submicromolar affinity, has a redox potential of -128 mV, and displays peroxidase activity. Here, we show the effect of aromatic residues in modulating the redox potential in the context of a membrane-soluble model system. We designed aromatic interactions with the heme through a single-point mutant, G25F, in which a phenylalanine is designed to dock against the porphyrin ring. This mutation results in roughly tenfold tighter binding to iron(III) protoporphyrin IX (K(d,app) = 6.5 × 10(-8) M), and lowers the redox potential of the cofactor to -172 mV. This work demonstrates that specific design features aimed at controlling the properties of bound cofactors can be introduced in a minimalist membrane hemoprotein model. The ability to modulate the redox potential of cofactors embedded in artificial membrane proteins is crucial for the design of electron transfer chains across membranes in functional photosynthetic devices.
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Affiliation(s)
- Sandip Shinde
- Department of Chemistry and Biochemistry, ASU, Tempe, AZ 85287, USA
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78
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Can M, Zoppellaro G, Andersson KK, Bren KL. Modulation of ligand-field parameters by heme ruffling in cytochromes c revealed by EPR spectroscopy. Inorg Chem 2011; 50:12018-24. [PMID: 22044358 DOI: 10.1021/ic201479q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electron paramagnetic resonance (EPR) spectra of variants of Hydrogenobacter thermophilus cytochrome c(552) (Ht c-552) and Pseudomonas aeruginosa cytochrome c(551) (Pa c-551) are analyzed to determine the effect of heme ruffling on ligand-field parameters. Mutations introduced at positions 13 and 22 in Ht c-552 were previously demonstrated to influence hydrogen bonding in the proximal heme pocket and to tune reduction potential (E(m)) over a range of 80 mV [Michel, L. V.; Ye, T.; Bowman, S. E. J.; Levin, B. D.; Hahn, M. A.; Russell, B. S.; Elliott, S. J.; Bren, K. L. Biochemistry 2007, 46, 11753-11760]. These mutations are shown here to also increase heme ruffling as E(m) decreases. The primary effect on electronic structure of increasing heme ruffling is found to be a decrease in the axial ligand-field term Δ/λ, which is proposed to arise from an increase in the energy of the d(xy) orbital. Mutations at position 7, previously demonstrated to influence heme ruffling in Pa c-551 and Ht c-552, are utilized to test this correlation between molecular and electronic structure. In conclusion, the structure of the proximal heme pocket of cytochromes c is shown to play a role in determining heme conformation and electronic structure.
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Affiliation(s)
- Mehmet Can
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, USA
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79
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Fonseca BM, Paquete CM, Salgueiro CA, Louro RO. The role of intramolecular interactions in the functional control of multiheme cytochromes c. FEBS Lett 2011; 586:504-9. [PMID: 21856299 DOI: 10.1016/j.febslet.2011.08.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 08/09/2011] [Indexed: 10/17/2022]
Abstract
Detailed thermodynamic and structural data measured in soluble monomeric multiheme cytochromes c provided the basis to investigate the functional significance of interactions between redox co-factors. The steep decay of intramolecular interactions with distance means that close proximity of the redox centers is necessary to modulate the intrinsic reduction potentials in a significant way. This ensures selection of specific populations during redox activity in addition to maintaining fast intramolecular electron transfer. Therefore, intramolecular interactions between redox co-factors play an important role in establishing the biological function of the protein by controlling how electrons flow through and are distributed among the co-factors.
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Affiliation(s)
- Bruno M Fonseca
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, EAN, 2780-157 Oeiras, Portugal
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80
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Direct probing of the folding/unfolding event of bovine hemoglobin at montmorillonite clay modified electrode by adsorptive-transfer voltammetry. Talanta 2011; 84:148-54. [DOI: 10.1016/j.talanta.2010.12.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2010] [Revised: 12/16/2010] [Accepted: 12/21/2010] [Indexed: 11/22/2022]
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81
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Alfonso-Prieto M, Oberhofer H, Klein ML, Rovira C, Blumberger J. Proton Transfer Drives Protein Radical Formation in Helicobacter pylori Catalase but Not in Penicillium vitale Catalase. J Am Chem Soc 2011; 133:4285-98. [DOI: 10.1021/ja1110706] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Alfonso-Prieto
- Computer Simulation & Modeling Laboratory, Parc Científic de Barcelona, Baldiri Reixac 4, 08028 Barcelona, Spain
- Institute for Computational Molecular Science, Temple University, 1900 North 12th Street, Philadelphia, Pennsylvania 19122, United States
| | - H. Oberhofer
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - M. L. Klein
- Institute for Computational Molecular Science, Temple University, 1900 North 12th Street, Philadelphia, Pennsylvania 19122, United States
| | - C. Rovira
- Computer Simulation & Modeling Laboratory, Parc Científic de Barcelona, Baldiri Reixac 4, 08028 Barcelona, Spain
- Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, 08028 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - J. Blumberger
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
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82
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Li T, Bonkovsky HL, Guo JT. Structural analysis of heme proteins: implications for design and prediction. BMC STRUCTURAL BIOLOGY 2011; 11:13. [PMID: 21371326 PMCID: PMC3059290 DOI: 10.1186/1472-6807-11-13] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 03/03/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND Heme is an essential molecule and plays vital roles in many biological processes. The structural determination of a large number of heme proteins has made it possible to study the detailed chemical and structural properties of heme binding environment. Knowledge of these characteristics can provide valuable guidelines in the design of novel heme proteins and help us predict unknown heme binding proteins. RESULTS In this paper, we constructed a non-redundant dataset of 125 heme-binding protein chains and found that these heme proteins encompass at least 31 different structural folds with all-α class as the dominating scaffold. Heme binding pockets are enriched in aromatic and non-polar amino acids with fewer charged residues. The differences between apo and holo forms of heme proteins in terms of the structure and the binding pockets have been investigated. In most cases the proteins undergo small conformational changes upon heme binding. We also examined the CP (cysteine-proline) heme regulatory motifs and demonstrated that the conserved dipeptide has structural implications in protein-heme interactions. CONCLUSIONS Our analysis revealed that heme binding pockets show special features and that most of the heme proteins undergo small conformational changes after heme binding, suggesting the apo structures can be used for structure-based heme protein prediction and as scaffolds for future heme protein design.
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Affiliation(s)
- Ting Li
- Cannon Research Center, Carolinas Medical Center, Charlotte, NC 28203, USA
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83
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Olea C, Kuriyan J, Marletta MA. Modulating heme redox potential through protein-induced porphyrin distortion. J Am Chem Soc 2011; 132:12794-5. [PMID: 20735135 DOI: 10.1021/ja106252b] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hemoproteins are ubiquitous in biology and are commonly involved in critical processes such as electron transfer, oxidative phosphorylation, and signal transduction. Both the protein environment and the heme cofactor contribute to generate the range of chemical properties needed for these diverse functions. Using the heme nitric oxide/oxygen binding (H-NOX) protein from the thermophilic bacterium Thermoanaerobacter tengcongensis, we have shown that heme electronic properties can be modulated by porphyrin distortion within the same protein scaffold without changing the heme ligation state or heme environment. The degree of heme distortion was found to be directly correlated to the electron density at the heme iron, as evidenced by dramatic changes in the heme redox potential and pK(a) of the distal ligand ((-)OH vs H(2)O). Protein-induced porphyrin distortion represents a new strategy to rationally tune the electronic properties of protein-bound porphyrins and could be used to engineer proteins with desired reactivity or functionality.
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Affiliation(s)
- Charles Olea
- Department of Molecular and Cell Biology, California Institute for Quantitative Biosciences, and Division of Physical Biosciences, University of California, Berkeley, Berkeley, California 94720-3220, USA
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84
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Smith LJ, Kahraman A, Thornton JM. Heme proteins--diversity in structural characteristics, function, and folding. Proteins 2010; 78:2349-68. [PMID: 20544970 DOI: 10.1002/prot.22747] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The characteristics of heme prosthetic groups and their binding sites have been analyzed in detail in a data set of nonhomologous heme proteins. Variations in the shape, volume, and chemical composition of the binding site, in the mode of heme binding and in the number and nature of heme-protein interactions are found to result in significantly different heme environments in proteins with different functions in biology. Differences are also seen in the properties of the apo states of the proteins. The apo states of proteins that bind heme permanently in their functional form show some disorder, ranging from local unfolding in the heme binding pocket to complete unfolding to give a random coil. In contrast, proteins that bind heme transiently are fully folded in their apo and holo states, presumably allowing both apo and holo forms to remain biologically active resisting aggregation or proteolysis. The principles identified here provide a framework for the design of de novo proteins that will exhibit tight heme ligand binding and for the identification of the function of structural genomic target proteins with heme ligands.
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Affiliation(s)
- Lorna J Smith
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford OX1 3QR, United Kingdom.
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85
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Grein F, Venceslau SS, Schneider L, Hildebrandt P, Todorovic S, Pereira IAC, Dahl C. DsrJ, an Essential Part of the DsrMKJOP Transmembrane Complex in the Purple Sulfur Bacterium Allochromatium vinosum, Is an Unusual Triheme Cytochrome c. Biochemistry 2010; 49:8290-9. [DOI: 10.1021/bi1007673] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fabian Grein
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn, Germany
| | - Sofia S. Venceslau
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da Republica, EAN, Apt 127, 2780-157 Oeiras, Portugal
| | - Lilian Schneider
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Smilja Todorovic
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da Republica, EAN, Apt 127, 2780-157 Oeiras, Portugal
| | - Inês A. C. Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da Republica, EAN, Apt 127, 2780-157 Oeiras, Portugal
| | - Christiane Dahl
- Institut für Mikrobiologie & Biotechnologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 168, D-53115 Bonn, Germany
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86
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Bowman SEJ, Bren KL. Variation and analysis of second-sphere interactions and axial histidinate character in c-type cytochromes. Inorg Chem 2010; 49:7890-7. [PMID: 20666367 PMCID: PMC2933145 DOI: 10.1021/ic100899k] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The electron-donating properties of the axial His ligand to heme iron in cytochromes c (cyts c) are found to be correlated with the midpoint reduction potential (E(m)) in variants of Hydrogenobacter thermophilus cytochrome c(552) (Ht cyt c(552)) in which mutations have been made in and near the Cys-X-X-Cys-His (CXXCH) heme-binding motif. To probe the strength of the His-Fe(III) interaction, we have measured (13)C nuclear magnetic resonance (NMR) chemical shifts for (13)CN(-) bound to heme iron trans to the axial His in Ht Fe(III) cyt c(552) variants. We observe a linear relationship between these (13)C chemical shifts and E(m), indicating that the His-Fe(III) bond strength correlates with E(m). To probe a conserved hydrogen bonding interaction between the axial His Hdelta1 and the backbone carbonyl of a Pro residue, we measured the pK(a) of the axial His Hdelta1 proton (pK(a(2))), which we propose to relate to the His-Fe(III) interaction, reduction potential, and local electrostatic effects. The observed linear relationship between the axial His (13)Cbeta chemical shift and E(m) is proposed to reflect histidinate (anionic) character of the ligand. A linear relationship also is seen between the average heme methyl (1)H chemical shift and E(m) which may reflect variation in axial His electron-donating properties or in the ruffling distortion of the heme plane. In summary, chemical shifts of the axial His and exogenous CN(-) bound trans to His are shown to be sensitive probes of the His-Fe(III) interaction in variants of Ht cyt c(552) and display trends that correlate with E(m).
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Affiliation(s)
- Sarah E. J. Bowman
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216
| | - Kara L. Bren
- Department of Chemistry, University of Rochester, Rochester, New York 14627-0216
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87
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Airola MV, Du J, Dawson JH, Crane BR. Heme binding to the Mammalian circadian clock protein period 2 is nonspecific. Biochemistry 2010; 49:4327-38. [PMID: 20411915 DOI: 10.1021/bi901945w] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mammalian circadian clock synchronizes physical and metabolic activity with the diurnal cycle through a transcriptional-posttranslational feedback loop. An additional feedback mechanism regulating clock timing has been proposed to involve oscillation in heme availability. Period 2 (PER2), an integral component in the negative feedback loop that establishes circadian rhythms in mammals, has been identified as a heme-binding protein. However, the majority of evidence for heme binding is based upon in vitro heme-binding assays. We sought to ascertain if these largely spectral assays could distinguish between specific and nonspecific heme interactions. Heme-binding properties by a number of other well-characterized proteins, all with no known biological role involving heme interaction, corresponded to those displayed by PER2. Site-directed mutants of putative heme-binding residues identified by MCD were unable to locate a specific heme-binding site on PER2. Protein film electrochemistry also indicates that heme binds PER2 nonspecifically on the protein surface. Our results establish the inability of qualitative in vitro assays to easily distinguish between specific and nonspecific heme binding. We conclude that heme binding to PER2 is likely to be nonspecific and does not involve the hydrophobic pocket within the PER2 PAS domains that in other PAS proteins commonly recognizes cofactors. These findings also question the significance of in vivo studies that implicate heme interactions with the clock proteins PER2 and nPAS2 in biological function.
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Affiliation(s)
- Michael V Airola
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
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88
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Kahraman A, Morris RJ, Laskowski RA, Favia AD, Thornton JM. On the diversity of physicochemical environments experienced by identical ligands in binding pockets of unrelated proteins. Proteins 2010; 78:1120-36. [PMID: 19927322 DOI: 10.1002/prot.22633] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Most function prediction methods that identify cognate ligands from binding site analyses work on the assumption of molecular complementarity. These approaches build on the conjectured complementarity of geometrical and physicochemical properties between ligands and binding sites so that similar binding sites will bind similar ligands. We found that this assumption does not generally hold for protein-ligand interactions and observed that it is not the chemical composition of ligand molecules that dictates the complementarity between protein and ligand molecules, but that the ligand's share within the functional mechanism of a protein determines the degree of complementarity. Here, we present for a set of cognate ligands a descriptive analysis and comparison of the physicochemical properties that each ligand experiences in various nonhomologous binding pockets. The comparisons in each ligand set reveal large variations in their experienced physicochemical properties, suggesting that the same ligand can bind to distinct physicochemical environments. In some protein ligand complexes, the variation was found to correlate with the electrochemical characteristic of ligand molecules, whereas in others it was disclosed as a prerequisite for the biochemical function of the protein. To achieve binding, proteins were observed to engage in subtle balancing acts between electrostatic and hydrophobic interactions to generate stabilizing free energies of binding. For the presented analysis, a new method for scoring hydrophobicity from molecular environments was developed showing high correlations with experimental determined desolvation energies. The presented results highlight the complexities of molecular recognition and underline the challenges of computational structural biology in developing methods to detect these important subtleties.
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Affiliation(s)
- Abdullah Kahraman
- European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SD, United Kingdom.
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89
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Mai Z, Zhao X, Dai Z, Zou X. Investigation of the chloride effect on hemoglobin by adsorptive transfer voltammetry. Anal Biochem 2010; 399:23-9. [PMID: 20005864 DOI: 10.1016/j.ab.2009.10.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 10/15/2009] [Accepted: 10/16/2009] [Indexed: 11/28/2022]
Abstract
A strategy of ex situ electrochemical method has been proposed for investigating the chloride effect on hemoglobin (Hb). Unlike the common electrochemical method that measures the chloride effect on Hb in bulk solution (in situ), the effects of chloride anion on Hb were investigated ex situ by adsorptive transfer voltammetry (AdTV) in this work. Gold electrode modified by self-assembled monolayer of 3-mercaptopropanoic acid (AuE/MPA) was prepared and then incubated in a series of Hb solutions containing different concentrations of chloride anion for adsorbing Hb-Cl (AuE/MPA/Hb-Cl). The resulting electrode was then measured in phosphate buffer solution by cyclic voltammetry. The corresponding voltammograms showed obvious promotion of the direct electron transfer of Hb with remarkable increase of peak currents, decrease of peak-to-peak separations, and negative shift of the formal potentials. As complementation, the adsorption behavior of Hb-Cl on AuE/MPA, the structural information of Hb-Cl, and the electrocatalytic ability of AuE/MPA/Hb-Cl toward hydrogen peroxide were investigated by surface plasmon resonance, circular dichroism spectrum, ultraviolet-visible spectrum and amperometry, respectively. The results indicate that the chloride effect resulted in more electroactive sites of Hb on the surface of electrode. Meanwhile, the specific and nonspecific interactions between Hb and chloride anion can be discriminated from the electrochemical parameters obtained by AdTV.
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Affiliation(s)
- Zhibin Mai
- School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, People's Republic of China.
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90
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Pearson JT, Siu S, Meininger DP, Wienkers LC, Rock DA. In Vitro Modulation of Cytochrome P450 Reductase Supported Indoleamine 2,3-Dioxygenase Activity by Allosteric Effectors Cytochrome b5 and Methylene Blue. Biochemistry 2010; 49:2647-56. [DOI: 10.1021/bi100022c] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Josh T. Pearson
- Biochemistry and Biophysics Group, Department of Pharmacokinetics and Drug Metabolism
| | | | | | - Larry C. Wienkers
- Biochemistry and Biophysics Group, Department of Pharmacokinetics and Drug Metabolism
| | - Dan A. Rock
- Biochemistry and Biophysics Group, Department of Pharmacokinetics and Drug Metabolism
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91
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A systematic investigation of multiheme c-type cytochromes in prokaryotes. J Biol Inorg Chem 2010; 15:559-71. [PMID: 20084531 DOI: 10.1007/s00775-010-0623-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 01/04/2010] [Indexed: 10/20/2022]
Abstract
Multiheme c-type cytochromes (MHCs) are metalloproteins that can play various biochemical roles, including enzymatic activity and electron transfer. As electron transfer proteins, the presence of multiple heme cofactors in the vicinity allows electrons to rapidly travel relatively long distances. MHCs are often characterized by relatively low structural complexity, with the heme cofactors being largely responsible for maintaining the structure in place, owing to the protein-heme covalent linkages. In this work, we analyzed an extensive ensemble of 594 complete prokaryotic proteomes, amounting to more than 1.9 million sequences, to characterize their content in MHCs. We identified 1,659 MHCs in 258 organisms. The presence of MHCs was found to correlate quite well with the capability of an organism to synthesize or take up heme. For two organisms, the presence of MHCs in the proteome could be taken as a hint to the presence of divergent heme uptake pathways. The most common numbers of heme-binding motifs in a sequence were four (25%) and two (23%), followed by five (13%) and ten (9.8%). The average protein-to-heme ratio was relatively similar for all MHCs, except diheme proteins, regardless of the number of motifs at around 60 +/- 30. The latter ratio could in favorable cases be a useful indicator for functional assignments of novel MHCs. Finally, we showed that the amount of structural information currently available for MHCs is limited with respect to the diversity of this broad class of metalloproteins. Experimental efforts in the structural investigation of MHCs are thus warranted.
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92
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Arias JI, Aller MA, Arias J. Surgical inflammation: a pathophysiological rainbow. J Transl Med 2009; 7:19. [PMID: 19309494 PMCID: PMC2667492 DOI: 10.1186/1479-5876-7-19] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 03/23/2009] [Indexed: 01/19/2023] Open
Abstract
Tetrapyrrole molecules are distributed in virtually all living organisms on Earth. In mammals, tetrapyrrole end products are closely linked to oxygen metabolism. Since increasingly complex trophic functional systems for using oxygen are considered in the post-traumatic inflammatory response, it can be suggested that tetrapyrrole molecules and, particularly their derived pigments, play a key role in modulating inflammation. In this way, the diverse colorfulness that the inflammatory response triggers during its evolution would reflect the major pathophysiological importance of these pigments in each one of its phases. Therefore, the need of exploiting this color resource could be considered for both the diagnosis and treatment of the inflammation.
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93
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Merlino A, Vergara A, Sica F, Mazzarella L. The bis-histidyl complex in hemoproteins: A detailed conformational analysis of database protein structures and the case of Antarctic fish hemoglobins. Mar Genomics 2009; 2:51-6. [DOI: 10.1016/j.margen.2009.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 04/09/2009] [Accepted: 04/16/2009] [Indexed: 10/20/2022]
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94
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Engineering heme binding sites in monomeric rop. J Biol Inorg Chem 2009; 14:497-505. [PMID: 19152012 DOI: 10.1007/s00775-009-0465-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 12/26/2008] [Indexed: 10/21/2022]
Abstract
Heme ligands were introduced in the hydrophobic core of an engineered monomeric ColE1 repressor of primer (rop-S55) in two different layers of the heptad repeat. Mutants rop-L63M/F121H (layer 1) and rop-L56H/L113H (layer 3) were found to bind heme with a K (D) of 1.1 +/- 0.2 and 0.47 +/- 0.07 microM, respectively. The unfolding of heme-bound and heme-free mutants, in the presence of guanidinium hydrochloride, was monitored by both circular dichroism and fluorescence spectroscopy. For the heme-bound rop mutants, the total free energy change was 0.5 kcal/mol higher in the layer 3 mutant compared with that in the layer1 mutant. Heme binding also stabilized these mutants by increasing the [DGobsH2O] by 1.4 and 1.8 kcal/mol in rop-L63M/F121H and rop-L56H/L113H, respectively. The reduction potentials measured by spectroelectrochemical titrations were calculated to be -154 +/- 2 mV for rop-56H/113H and -87.5 +/- 1.2 mV for rop-L63M/F121H. The mutant designed to bind heme in a more buried environment (layer 3) showed tighter heme binding, a higher stability, and a different reduction potential compared with the mutant designed to bind heme in layer 1.
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95
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Fufezan C, Zhang J, Gunner MR. Ligand preference and orientation in b- and c-type heme-binding proteins. Proteins 2008; 73:690-704. [PMID: 18491383 DOI: 10.1002/prot.22097] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Hemes are often incorporated into designed proteins. The importance of the heme ligand type and its orientation is still a matter of debate. Here, heme ligands and ligand orientation were investigated using a nonredundant (87 structures) and a redundant (1503 structures) set of structures to compare and contrast design features of natural b- and c-type heme-binding proteins. Histidine is the most common ligand. Marked differences in ligation motifs between b- and c-type hemes are higher occurrence of His-Met in c-type heme binding motifs (16.4% vs. 1.4%) and higher occurrence of exchangeable, small molecules in b-type heme binding motifs (67.6% vs. 9.9%). Histidine ligands that are part of the c-type CXXCH heme-binding motif show a distinct asymmetric distribution of orientation. They tend to point between either the heme propionates or between the NA and NB heme nitrogens. Molecular mechanics calculations show that this asymmetry is due to the bonded constraints of the covalent attachment between the heme and the protein. In contrast, the orientations of b-type hemes histidine ligands are found evenly distributed with no preference. Observed histidine heme ligand orientations show no dominating influence of electrostatic interactions between the heme propionates and the ligands. Furthermore, ligands in bis-His hemes are found more frequently perpendicular rather than parallel to each other. These correlations support energetic constraints on ligands that can be used in designing proteins.
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Affiliation(s)
- Christian Fufezan
- Physics Department, City College of New York, New York, New York 10031, USA.
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96
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Bowman SEJ, Bren KL. The chemistry and biochemistry of heme c: functional bases for covalent attachment. Nat Prod Rep 2008; 25:1118-30. [PMID: 19030605 DOI: 10.1039/b717196j] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A discussion of the literature concerning the synthesis, function, and activity of heme c-containing proteins is presented. Comparison of the properties of heme c, which is covalently bound to protein, is made to heme b, which is bound noncovalently. A question of interest is why nature uses biochemically expensive heme c in many proteins when its properties are expected to be similar to heme b. Considering the effects of covalent heme attachment on heme conformation and on the proximal histidine interaction with iron, it is proposed that heme attachment influences both heme reduction potential and ligand-iron interactions.
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Affiliation(s)
- Sarah E J Bowman
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA
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97
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Beller HR, Legler TC, Bourguet F, Letain TE, Kane SR, Coleman MA. Identification of c-type cytochromes involved in anaerobic, bacterial U(IV) oxidation. Biodegradation 2008; 20:45-53. [DOI: 10.1007/s10532-008-9198-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 04/29/2008] [Indexed: 10/22/2022]
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