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Schultz CR, Johnson M, Wallace JG. Effects of Inbreeding on Microbial Community Diversity of Zea mays. Microorganisms 2023; 11:microorganisms11040879. [PMID: 37110300 PMCID: PMC10145435 DOI: 10.3390/microorganisms11040879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/14/2023] [Accepted: 03/28/2023] [Indexed: 03/31/2023] Open
Abstract
Heterosis, also known as hybrid vigor, is the basis of modern maize production. The effect of heterosis on maize phenotypes has been studied for decades, but its effect on the maize-associated microbiome is much less characterized. To determine the effect of heterosis on the maize microbiome, we sequenced and compared the bacterial communities of inbred, open pollinated, and hybrid maize. Samples covered three tissue types (stalk, root, and rhizosphere) in two field experiments and one greenhouse experiment. Bacterial diversity was more affected by location and tissue type than genetic background for both within-sample (alpha) and between-sample (beta) diversity. PERMANOVA analysis similarly showed that tissue type and location had significant effects on the overall community structure, whereas the intraspecies genetic background and individual plant genotypes did not. Differential abundance analysis identified only 25 bacterial ASVs that significantly differed between inbred and hybrid maize. Predicted metagenome content was inferred with Picrust2, and it also showed a significantly larger effect of tissue and location than genetic background. Overall, these results indicate that the bacterial communities of inbred and hybrid maize are often more similar than they are different and that non-genetic effects are generally the largest influences on the maize microbiome.
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2
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Transcriptomic Analysis of the Molecular Response Mechanism of Microcystis aeruginosa to Iron Limitation Stress. WATER 2022. [DOI: 10.3390/w14111679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Iron is an essential micronutrient for cyanobacteria. It is involved in physiological activities such as photosynthesis, respiration, and the synthesis of pigments. The impact of iron limitation on planktonic algae growth occurs in surface oceans globally, as well as in freshwater ecosystems. However, the molecular and physiological effects and response mechanism of cyanobacteria under iron-limited conditions have not been reported in detail. In this study, the effects of iron limitation on the cell density, chlorophyll content, and photosynthetic activity of Microcystis aeruginosa were determined, and transcriptome sequencing was undertaken. In a severely iron-deficient environment, the cell density and chlorophyll-a content of M. aeruginosa were significantly lower than in the iron-rich group (a 55.42% and 83.51% reduction, respectively). Similarly, the photosynthetic efficiency of M. aeruginosa was also inhibited by iron deficiency, and the maximum photochemical efficiency (Fv/Fm) of the severe iron deficiency group was only 66.72% of the control group. The transcriptome results showed that to cope with the iron-deficient environment, most genes involved in iron absorption and transport in M. aeruginosa were up-regulated. In particular, the fur and perR genes that regulate the iron uptake regulatory protein (Fur) were both up-regulated. Due to the high demand for iron in the photosynthetic electron transport chain of M. aeruginosa, most photosynthesis-related genes were down-regulated, for example, petJ, which regulates iron-containing cytochrome c6. In contrast, most of the genes related to glycolysis and respiration were up-regulated. These changes in gene expression may be a survival strategy for M. aeruginosa to cope with a long-term iron-deficient environment. This study provides insights into the molecular response mechanism of M. aeruginosa under iron limitation stress.
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Pernil R, Schleiff E. Metalloproteins in the Biology of Heterocysts. Life (Basel) 2019; 9:E32. [PMID: 30987221 PMCID: PMC6616624 DOI: 10.3390/life9020032] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/18/2019] [Accepted: 03/28/2019] [Indexed: 12/15/2022] Open
Abstract
Cyanobacteria are photoautotrophic microorganisms present in almost all ecologically niches on Earth. They exist as single-cell or filamentous forms and the latter often contain specialized cells for N₂ fixation known as heterocysts. Heterocysts arise from photosynthetic active vegetative cells by multiple morphological and physiological rearrangements including the absence of O₂ evolution and CO₂ fixation. The key function of this cell type is carried out by the metalloprotein complex known as nitrogenase. Additionally, many other important processes in heterocysts also depend on metalloproteins. This leads to a high metal demand exceeding the one of other bacteria in content and concentration during heterocyst development and in mature heterocysts. This review provides an overview on the current knowledge of the transition metals and metalloproteins required by heterocysts in heterocyst-forming cyanobacteria. It discusses the molecular, physiological, and physicochemical properties of metalloproteins involved in N₂ fixation, H₂ metabolism, electron transport chains, oxidative stress management, storage, energy metabolism, and metabolic networks in the diazotrophic filament. This provides a detailed and comprehensive picture on the heterocyst demands for Fe, Cu, Mo, Ni, Mn, V, and Zn as cofactors for metalloproteins and highlights the importance of such metalloproteins for the biology of cyanobacterial heterocysts.
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Affiliation(s)
- Rafael Pernil
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt am Main, Germany.
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt am Main, Germany.
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany.
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Straβe 15, 60438 Frankfurt am Main, Germany.
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Torrado A, Ramírez-Moncayo C, Navarro JA, Mariscal V, Molina-Heredia FP. Cytochrome c 6 is the main respiratory and photosynthetic soluble electron donor in heterocysts of the cyanobacterium Anabaena sp. PCC 7120. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1860:60-68. [PMID: 30414412 DOI: 10.1016/j.bbabio.2018.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 10/20/2018] [Accepted: 11/07/2018] [Indexed: 12/27/2022]
Abstract
Cytochrome c6 is a soluble electron carrier, present in all known cyanobacteria, that has been replaced by plastocyanin in plants. Despite their high structural differences, both proteins have been reported to be isofunctional in cyanobacteria and green algae, acting as alternative electron carriers from the cytochrome b6-f complex to photosystem I or terminal oxidases. We have investigated the subcellular localization of both cytochrome c6 and plastocyanin in the heterocyst-forming cyanobacterium Anabaena sp. PCC 7120 grown in the presence of combined nitrogen and under diazotrophic conditions. Our studies conclude that cytochrome c6 is expressed at significant levels in heterocysts, even in the presence of copper, condition in which it is strongly repressed in vegetative cells. However, the copper-dependent regulation of plastocyanin is not altered in heterocysts. In addition, in heterocysts, cytochrome c6 has shown to be the main soluble electron carrier to cytochrome c oxidase-2 in respiration. A cytochrome c6 deletion mutant is unable to grow under diazotrophic conditions in the presence of copper, suggesting that cytochrome c6 plays an essential role in the physiology of heterocysts that cannot be covered by plastocyanin.
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Affiliation(s)
- Alejandro Torrado
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Sevilla, Spain; Departamento de Bioquímica Vegetal y Biología Molecular, Universidad de Sevilla, Sevilla, Spain
| | - Carmen Ramírez-Moncayo
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Sevilla, Spain
| | - José A Navarro
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Sevilla, Spain
| | - Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Sevilla, Spain.
| | - Fernando P Molina-Heredia
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Sevilla, Spain; Departamento de Bioquímica Vegetal y Biología Molecular, Universidad de Sevilla, Sevilla, Spain.
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5
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Torrado A, Valladares A, Puerto-Galán L, Hervás M, Navarro JA, Molina-Heredia FP. Cyt c6-3: A New Isoform of Photosynthetic Cyt c6 Exclusive to Heterocyst-Forming Cyanobacteria. PLANT & CELL PHYSIOLOGY 2017; 58:256-265. [PMID: 28007969 DOI: 10.1093/pcp/pcw184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/21/2016] [Indexed: 06/06/2023]
Abstract
All known cyanobacteria contain Cyt c6, a small soluble electron carrier protein whose main function is to transfer electrons from the Cyt b6f complex to PSI, although it is also involved in respiration. We have previously described a second isoform of this protein, the Cyt c6-like, whose function remains unknown. Here we describe a third isoform of Cyt c6 (here called Cytc6-3), which is only found in heterocyst-forming filamentous cyanobacteria. Cyt c6-3 is expressed in vegetative cells but is specifically repressed in heterocysts cells under diazotrophic growth conditions. Although there is a close structural similarity between Cyt c6-3 and Cyt c6 related to the general protein folding, Cyt c6-3 presents differential electrostatic surface features as compared with Cyt c6, its expression is not copper dependent and has a low reactivity towards PSI. According to the different expression pattern, functional reactivity and structural properties, Cyt c6-3 has to play an as yet to be defined regulatory role related to heterocyst differentiation.
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Affiliation(s)
- Alejandro Torrado
- School of Medicine, Department of Anatomy and Neurobiology, Medical Science Campus of the University of Puerto Rico (MCS-UPR), San Juan, PR, USA
| | - Ana Valladares
- Department of Environmental, Earth and Geospatial Sciences, North Carolina Central University, Durham, North Carolina, USA
| | - Leonor Puerto-Galán
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda Américo Vespucio, Sevilla, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas Seville, Spain
| | - José A Navarro
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas Seville, Spain
| | - Fernando P Molina-Heredia
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda Américo Vespucio, Sevilla, Spain
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Moreno-Beltrán B, Díaz-Moreno I, González-Arzola K, Guerra-Castellano A, Velázquez-Campoy A, De la Rosa MA, Díaz-Quintana A. Respiratory complexes III and IV can each bind two molecules of cytochrome c at low ionic strength. FEBS Lett 2015; 589:476-83. [PMID: 25595453 DOI: 10.1016/j.febslet.2015.01.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/26/2014] [Accepted: 01/07/2015] [Indexed: 12/22/2022]
Abstract
The transient interactions of respiratory cytochrome c with complexes III and IV is herein investigated by using heterologous proteins, namely human cytochrome c, the soluble domain of plant cytochrome c1 and bovine cytochrome c oxidase. The binding molecular mechanisms of the resulting cross-complexes have been analyzed by Nuclear Magnetic Resonance and Isothermal Titration Calorimetry. Our data reveal that the two cytochrome c-involving adducts possess a 2:1 stoichiometry - that is, two cytochrome c molecules per adduct - at low ionic strength. We conclude that such extra binding sites at the surfaces of complexes III and IV can facilitate the turnover and sliding of cytochrome c molecules and, therefore, the electron transfer within respiratory supercomplexes.
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Affiliation(s)
- Blas Moreno-Beltrán
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain
| | - Irene Díaz-Moreno
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain.
| | - Katiuska González-Arzola
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain
| | - Alejandra Guerra-Castellano
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain
| | - Adrián Velázquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI) - Joint Unit BIFI-IQFR (CSIC), Universidad de Zaragoza, Mariano Esquillor s/n, 50018 Zaragoza, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain; Fundacion ARAID, Government of Aragon, Maria de Luna 11, 50018 Zaragoza, Spain
| | - Miguel A De la Rosa
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain
| | - Antonio Díaz-Quintana
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla-CSIC, Avda. Américo Vespucio 49, Sevilla 41092, Spain
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7
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Wang XQ, Jiang HB, Zhang R, Qiu BS. Inactivation of thepetEgene encoding plastocyanin causes different photosynthetic responses in cyanobacteriumSynechocystisPCC 6803 under light-dark photoperiod and continuous light conditions. FEMS Microbiol Lett 2013; 341:106-14. [DOI: 10.1111/1574-6968.12101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Revised: 02/01/2013] [Accepted: 02/06/2013] [Indexed: 12/01/2022] Open
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8
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Kallas T. Cytochrome b 6 f Complex at the Heart of Energy Transduction and Redox Signaling. PHOTOSYNTHESIS 2012. [DOI: 10.1007/978-94-007-1579-0_21] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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9
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Reyes-Sosa FM, Gil-Martínez J, Molina-Heredia FP. Cytochrome c6-like protein as a putative donor of electrons to photosystem I in the cyanobacterium Nostoc sp. PCC 7119. PHOTOSYNTHESIS RESEARCH 2011; 110:61-72. [PMID: 21984388 DOI: 10.1007/s11120-011-9694-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 09/22/2011] [Indexed: 05/31/2023]
Abstract
Most organisms performing oxygenic photosynthesis contain either cytochrome c(6) or plastocyanin, or both, to transfer electrons from cytochrome b(6)-f to photosystem I. Even though plastocyanin has superseded cytochrome c(6) along evolution, plants contain a modified cytochrome c(6), the so called cytochrome c(6A), whose function still remains unknown. In this article, we describe a second cytochrome c(6) (the so called cytochrome c(6)-like protein), which is found in some cyanobacteria but is phylogenetically more related to plant cytochrome c(6A) than to cyanobacterial cytochrome c(6). In this article, we conclude that the cytochrome c(6)-like protein is a putative electron donor to photosystem I, but does play a role different to that of cytochrome c(6) and plastocyanin as it cannot accept electrons from cytochrome f. The existence of this third electron donor to PSI could explain why some cyanobacteria are able to grow photoautotrophically in the absence of both cytochrome c(6) and plastocyanin. In any way, the Cyt c(6)-like protein from Nostoc sp. PCC 7119 would be potentially utilized for the biohydrogen production, using cell-free photosystem I catalytic nanoparticles.
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Affiliation(s)
- Francisco M Reyes-Sosa
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla y CSIC, Américo Vespucio 49, 41092 Sevilla, Spain
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10
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Bernroitner M, Tangl D, Lucini C, Furtmüller PG, Peschek GA, Obinger C. Cyanobacterial cytochrome cM: Probing its role as electron donor for CuA of cytochrome c oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:135-43. [DOI: 10.1016/j.bbabio.2008.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 12/05/2008] [Accepted: 12/09/2008] [Indexed: 11/26/2022]
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11
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Bernroitner M, Zamocky M, Pairer M, Furtmüller PG, Peschek GA, Obinger C. Heme-copper oxidases and their electron donors in cyanobacterial respiratory electron transport. Chem Biodivers 2008; 5:1927-1961. [PMID: 18972533 DOI: 10.1002/cbdv.200890180] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cyanobacteria are the paradigmatic organisms of oxygenic (plant-type) photosynthesis and aerobic respiration. Since there is still an amazing lack of knowledge on the role and mechanism of their respiratory electron transport, we have critically analyzed all fully or partially sequenced genomes for heme-copper oxidases and their (putative) electron donors cytochrome c(6), plastocyanin, and cytochrome c(M). Well-known structure-function relationships of the two branches of heme-copper oxidases, namely cytochrome c (aa(3)-type) oxidase (COX) and quinol (bo-type) oxidase (QOX), formed the base for a critical inspection of genes and ORFs found in cyanobacterial genomes. It is demonstrated that at least one operon encoding subunits I-III of COX is found in all cyanobacteria, whereas many non-N(2)-fixing species lack QOX. Sequence analysis suggests that both cyanobacterial terminal oxidases should be capable of both the four-electron reduction of dioxygen and proton pumping. All diazotrophic organisms have at least one operon that encodes QOX. In addition, the highly refined specialization in heterocyst forming Nostocales is reflected by the presence of two paralogs encoding COX. The majority of cyanobacterial genomes contain one gene or ORF for plastocyanin and cytochrome c(M), whereas 1-4 paralogs for cytochrome c(6) were found. These findings are discussed with respect to published data about the role of respiration in wild-type and mutated cyanobacterial strains in normal metabolism, stress adaptation, and nitrogen fixation. A model of the branched electron-transport pathways downstream of plastoquinol in cyanobacteria is presented.
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Affiliation(s)
- Margit Bernroitner
- Department of Chemistry, Division of Biochemistry, BOKU-University of Natural Resources and Applied Life Sciences, Muthgasse 18, A-1190 Vienna
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12
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Rodríguez-Roldán V, García-Heredia JM, Navarro JA, Rosa MADL, Hervás M. Effect of Nitration on the Physicochemical and Kinetic Features of Wild-Type and Monotyrosine Mutants of Human Respiratory Cytochrome c. Biochemistry 2008. [DOI: 10.1021/bi801329s] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vicente Rodríguez-Roldán
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - José Manuel García-Heredia
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - José A. Navarro
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - Miguel A. De la Rosa
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas, Sevilla, Spain
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13
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Pereira MM, Sousa FL, Veríssimo AF, Teixeira M. Looking for the minimum common denominator in haem-copper oxygen reductases: towards a unified catalytic mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:929-34. [PMID: 18515066 DOI: 10.1016/j.bbabio.2008.05.441] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Revised: 04/15/2008] [Accepted: 05/16/2008] [Indexed: 10/22/2022]
Abstract
Haem-copper oxygen reductases are transmembrane protein complexes that reduce dioxygen to water and pump protons across the mitochondrial or periplasmatic membrane, contributing to the transmembrane difference of electrochemical potential. Seven years ago we proposed a classification of these enzymes into three different families (A, B and C), based on the amino acid residues of their proton channels and amino acid sequence comparison, later supported by the so far identified characteristics of the catalytic centre of members from each family. The three families have in common the same general structural fold of the catalytic subunit, which contains the same or analogous prosthetic groups, and proton channels. These observations raise the hypothesis that the mechanisms for dioxygen reduction, proton pumping and the coupling of the two processes may be the same for all these enzymes. Under this hypothesis, they should be performed and controlled by the same or equivalent elements/events, and the identification of retained elements in all families will reveal their importance and may prompt the definition of the enzyme operating mode. Thus, we believe that the search for a minimum common denominator has a crucial importance, and in this article we highlight what is already established for the haem-copper oxygen reductases and emphasize the main questions still unanswered in a comprehensive basis.
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Affiliation(s)
- Manuela M Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República - EAN, 2780-157 Oeiras, Portugal.
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14
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Rodríguez-Roldán V, García-Heredia JM, Navarro JA, Hervás M, De la Cerda B, Molina-Heredia FP, De la Rosa MA. A comparative kinetic analysis of the reactivity of plant, horse, and human respiratory cytochrome c towards cytochrome c oxidase. Biochem Biophys Res Commun 2006; 346:1108-13. [PMID: 16782050 DOI: 10.1016/j.bbrc.2006.06.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Accepted: 06/03/2006] [Indexed: 01/29/2023]
Abstract
Two synthetic genes coding for human and Arabidopsis cytochrome c, respectively, have been designed and constructed, and the recombinant proteins have been over-expressed in Escherichia coli cells. Thus a comparative analysis of the two heme proteins, including horse cytochrome c as a reference, has been performed. In addition to their physico-chemical properties, the redox behavior of the three proteins has been analyzed by following the kinetics of both their reduction by flavin semiquinones (lumiflavin, riboflavin, and FMN) and oxidation by cytochrome c oxidase. The resulting data indicate that the accessibility and electrostatic charge of the active site do not differ in a significant way among the three proteins, but human cytochrome c exhibits some intriguing differences when interacting with cytochrome c oxidase that could be related to the amino acid changes underwent by the latter along evolution.
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Affiliation(s)
- Vicente Rodríguez-Roldán
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla y CSIC, Centro de Investigaciones Científicas Isla de la Cartuja, Sevilla, Spain
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15
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Durán RV, Hervás M, De la Cerda B, De la Rosa MA, Navarro JA. A Laser Flash-Induced Kinetic Analysis of in Vivo Photosystem I Reduction by Site-Directed Mutants of Plastocyanin and Cytochrome c6 in Synechocystis sp. PCC 6803. Biochemistry 2005; 45:1054-60. [PMID: 16411782 DOI: 10.1021/bi052090w] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In cyanobacteria, plastocyanin and cytochrome c6 are two soluble metalloproteins which can alternately serve as electron donors to photosystem I. From site-directed mutagenesis studies in vitro, it is well-established that both hydrophobic and electrostatic forces are involved in the interaction between the donor proteins and photosystem I. Hence, two isofunctional areas, a hydrophobic one in the north and an acidic one in the east, have been described on the surface of both electron donors. In this work, we have tested the relevance of such kinds of interactions in the photosystem I reduction inside the cell. Several plastocyanin and cytochrome c6 site-directed mutant strains affecting both the acidic and hydrophobic regions of the two metalloproteins, which were previously characterized in vitro, have been constructed. The photosystem I reduction kinetics of the different mutants have been analyzed by laser flash absorption spectroscopy. Relevant differences have been found between the in vitro and in vivo results, mainly regarding the role played by the electrostatic interactions. Adding positive electrostatic charges to the acidic patch of plastocyanin and cytochrome c6 promotes an enhanced interaction with photosystem I in vitro but yields the opposite effect in vivo. These discrepancies are discussed in view of the different environmental conditions, in vitro and in vivo, for the reaction mechanism of photosystem I reduction, namely, differential interaction of the electron donors with the thylakoidal membrane and kinetics of donor exchange.
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Affiliation(s)
- Raúl V Durán
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla y Consejo Superior de Investigaciones Científicas, Sevilla, Spain
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