60 results on '"De la Cerda, Berta"'
Search Results
52. A proteomic approach to iron and copper homeostasis in cyanobacteria.
- Author
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De la Cerda, Berta, Castielli, Ornella, Dur´n, Raúl V., Navarro, José A., Hervás, Manuel, and De la Rosa, Miguel A.
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CYANOBACTERIA , *HOMEOSTASIS , *IRON , *COPPER , *PLASTOCYANIN , *CYTOCHROME c , *PROTEOMICS - Abstract
Cyanobacteria, which are considered to be the chloroplast precursors, are significant contributors to global photosynthetic productivity. The ample variety of membrane and soluble proteins containing different metals (mainly, iron and copper) has made these organisms develop a complex homeostasis with different mechanisms and tight regulation processes to fulfil their metal requirements in a changing environment. Cell metabolism is so adapted as to synthesize alternative proteins depending on the relative metal availabilities. In particular, plastocyanin, a copper protein, and cytochrome c6, a haem protein, can replace each other to play the same physiological role as electron carriers in photosynthesis and respiration, with the synthesis of one protein or another being regulated by copper concentration in the medium. The unicellular cyanobacterium Synechocystis sp. PCC 6803 has been widely used as a model system because of completion of its genome sequence and the ease of its genetic manipulation, with a lot of proteomic work being done. In this review article, we focus on the functional characterization of knockout Synechocystis mutants for plastocyanin and cytochrome c6, and discuss the ongoing proteomic analyses performed at varying copper concentrations to investigate the cyanobacterial metal homeostasis and cell response to changing environmental conditions. [ABSTRACT FROM AUTHOR] more...
- Published
- 2007
53. 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.
- Author
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Durán, Raúl V., Hervás, Manuel, De la Cerda, Berta, De la Rosa, Miguel A., and Navarro, José A.
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- 2006
- Full Text
- View/download PDF
54. A comparative structural and functional analysis of cyanobacterial plastocyanin and cytochrome c6as alternative electron donors to Photosystem I
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Díaz-Quintana, Antonio, Navarro, José, Hervás, Manuel, Molina-Heredia, Fernando, De la Cerda, Berta, and De la Rosa, Miguel
- Abstract
Plastocyanin and cytochrome c6are two soluble metalloproteins that act as alternative electron carriers between the membrane-embedded complexes cytochromes b6fand Photosystem I. Despite plastocyanin and cytochrome c6differing in the nature of their redox center (one is a copper protein, the other is a heme protein) and folding pattern (one is a β-barrel, the other consists of α-helices), they are exchangeable in green algae and cyanobacteria. In fact, the two proteins share a number of structural similarities that allow them to interact with the same membrane complexes in a similar way. The kinetic and thermodynamic analysis of Photosystem I reduction by plastocyanin and cytochrome c6reveals that the same factors govern the reaction mechanism within the same organism, but differ from one another. In cyanobacteria, in particular, the electrostatic and hydrophobic interactions between Photosystem I and its electron donors have been analyzed using the wild-type protein species and site-directed mutants. A number of residues similarly conserved in the two proteins have been shown to be critical for the electron transfer reaction. Cytochrome c6does contain two functional areas that are equivalent to those previously described in plastocyanin: one is a hydrophobic patch for electron transfer (site 1), and the other is an electrically charged area for complex formation (site 2). Each cyanobacterial protein contains just one arginyl residue, similarly located between sites 1 and 2, that is essential for the redox interaction with Photosystem I. more...
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- 2003
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55. Mutations in both leucine 12 and lysine 33 in plastocyanin from Synechocystissp. PCC 6803 induce drastic changes in the hydrophobic interactions with Photosystem I
- Author
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Díaz-Quintana, Antonio, De la Cerda, Berta, Hervás, Manuel, Navarro, José, and De la Rosa, Miguel
- Abstract
The role played by the residues Leu12 and Lys33 – which are both located at the north hydrophobic patch of plastocyanin – in the interaction of the copper protein with Photosystem I from the cyanobacterium Synechocystissp. PCC 6803 has been investigated by site-directed mutagenesis. A thermodynamic analysis of PS I reduction by wild-type and mutant plastocyanins has been performed by laser-flash absorption spectroscopy. In all cases, the electron transfer is impaired by mutations, which induce drastic changes in the apparent activation entropy of the overall reaction. Substitution of Leu12 by alanine specifically affects the hydrophobic interactions with PS I, whereas replacement of Lys33 by glutamate not only induces local electrostatic changes, but also alters the hydrophobic interactions with the photosystem. The thermodynamic analysis of the reactivity of K33E mutant towards PS I reveals that the effect of the mutation can be reversed by addition of magnesium cations, which probably bind at a place close to Glu33. The electrostatic surface potential does thus modulate the hydrophobic interactions with PS I by altering the solvent accessibility of some surface residues. more...
- Published
- 2002
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56. Site-directed Mutagenesis of Cytochromec6from Synechocystissp. PCC 6803
- Author
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De la Cerda, Berta, Dı́az-Quintana, Antonio, Navarro, José A., Hervás, Manuel, and De la Rosa, Miguel A.
- Abstract
This paper reports the first site-directed mutagenesis analysis of any cytochrome c6, a heme protein that performs the same function as the copper-protein plastocyanin in the electron transport chain of photosynthetic organisms. Photosystem I reduction by the mutants of cytochromec6from the cyanobacteriumSynechocystissp. PCC 6803 has been studied by laser flash absorption spectroscopy. Their kinetic efficiency and thermodynamic properties have been compared with those of plastocyanin mutants from the same organism. Such a comparative study reveals that aspartates at positions 70 and 72 in cytochrome c6are located in an acidic patch that may be isofunctional with the well known “south-east” patch of plastocyanin. Calculations of surface electrostatic potential distribution in the mutants of cytochromec6and plastocyanin indicate that the changes in protein reactivity depend on the surface electrostatic potential pattern rather than on the net charge modification induced by mutagenesis. Phe-64, which is close to the heme group and may be the counterpart of Tyr-83 in plastocyanin, does not appear to be involved in the electron transfer to photosystem I. In contrast, Arg-67, which is at the edge of the cytochrome c6acidic area, seems to be crucial for the interaction with the reaction center. more...
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- 1999
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57. The 2.15 Å crystal structure of a triple mutant plastocyanin from the cyanobacterium Synechocystissp. PCC 680311Edited by R. Huber
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Romero, Antonio, De la Cerda, Berta, Varela, Paloma F, Navarro, José A, Hervás, Manuel, and De la Rosa, Miguel A
- Abstract
The crystal structure of the triple mutant A42D/D47P/A63L plastocyanin from the cyanobacterium Synechocystissp. PCC 6803 has been determined by Patterson search methods using the known structure of the poplar protein. Crystals of the triple mutant A42D/D47P/A63L, which are stable for days in its oxidized form, were grown from ammonium sulfate, with the cell constants a= b= 34.3 Å and c= 111.8 Å belonging to space group P3221. The structure was refined using restrained crystallographic refinement to an R-factor of 16.7% for 4070 independent reflections between 8.0 and 2.15 Å with intensities greater than 2σ(I), with root mean square deviations of 0.013 Å and 1.63° from ideal bond lengths and bond angles, respectively. The final model comprises 727 non-hydrogen protein atoms within 98 residues, 75 water molecules and a single copper ion. The overall tertiary fold of Synechocystisplastocyanin consists of a compact ellipsoidal β-sandwich structure made up of two β-sheets embracing a hydrophobic core. Each sheet contains parallel and antiparallel β-strands. In addition to the β-sheets, the structure contains an α-helix from Pro47 to Lys54 that follows β-strand 4. The three-dimensional structure of Synechocystisplastocyanin is thus similar to those reported for the copper protein isolated from eukaryotic organisms and, in particular, from the cyanobacterium Anabaena variabilis, the only cyanobacterial plastocyanin structure available so far. The molecule holds an hydrophobic region surrounding His87, as do other plastocyanins, but the lack of negatively charged residues at the putative distant remote site surrounding Tyr83 could explain why the Synechocystisprotein exhibits a collisional reaction mechanism for electron transfer to photosystem I (PSI), which involves no formation of the transient plastocyanin-PSI complex kinetically observed in green algae and higher plants. more...
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- 1998
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58. Cost-effective sequence analysis of 113 genes in 1,192 probands with retinitis pigmentosa and Leber congenital amaurosis.
- Author
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Panneman DM, Hitti-Malin RJ, Holtes LK, de Bruijn SE, Reurink J, Boonen EGM, Khan MI, Ali M, Andréasson S, De Baere E, Banfi S, Bauwens M, Ben-Yosef T, Bocquet B, De Bruyne M, de la Cerda B, Coppieters F, Farinelli P, Guignard T, Inglehearn CF, Karali M, Kjellström U, Koenekoop R, de Koning B, Leroy BP, McKibbin M, Meunier I, Nikopoulos K, Nishiguchi KM, Poulter JA, Rivolta C, Rodríguez de la Rúa E, Saunders P, Simonelli F, Tatour Y, Testa F, Thiadens AAHJ, Toomes C, Tracewska AM, Tran HV, Ushida H, Vaclavik V, Verhoeven VJM, van de Vorst M, Gilissen C, Hoischen A, Cremers FPM, and Roosing S more...
- Abstract
Introduction: Retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA) are two groups of inherited retinal diseases (IRDs) where the rod photoreceptors degenerate followed by the cone photoreceptors of the retina. A genetic diagnosis for IRDs is challenging since >280 genes are associated with these conditions. While whole exome sequencing (WES) is commonly used by diagnostic facilities, the costs and required infrastructure prevent its global applicability. Previous studies have shown the cost-effectiveness of sequence analysis using single molecule Molecular Inversion Probes (smMIPs) in a cohort of patients diagnosed with Stargardt disease and other maculopathies. Methods: Here, we introduce a smMIPs panel that targets the exons and splice sites of all currently known genes associated with RP and LCA, the entire RPE65 gene, known causative deep-intronic variants leading to pseudo-exons, and part of the RP17 region associated with autosomal dominant RP, by using a total of 16,812 smMIPs. The RP-LCA smMIPs panel was used to screen 1,192 probands from an international cohort of predominantly RP and LCA cases. Results and discussion: After genetic analysis, a diagnostic yield of 56% was obtained which is on par with results from WES analysis. The effectiveness and the reduced costs compared to WES renders the RP-LCA smMIPs panel a competitive approach to provide IRD patients with a genetic diagnosis, especially in countries with restricted access to genetic testing., Competing Interests: PS is an employee of Molecular Loop Biosciences Inc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Panneman, Hitti-Malin, Holtes, de Bruijn, Reurink, Boonen, Khan, Ali, Andréasson, De Baere, Banfi, Bauwens, Ben-Yosef, Bocquet, De Bruyne, Cerda, Coppieters, Farinelli, Guignard, Inglehearn, Karali, Kjellström, Koenekoop, de Koning, Leroy, McKibbin, Meunier, Nikopoulos, Nishiguchi, Poulter, Rivolta, Rodríguez de la Rúa, Saunders, Simonelli, Tatour, Testa, Thiadens, Toomes, Tracewska, Tran, Ushida, Vaclavik, Verhoeven, van de Vorst, Gilissen, Hoischen, Cremers and Roosing.) more...
- Published
- 2023
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59. A comparative kinetic analysis of the reactivity of plant, horse, and human respiratory cytochrome c towards cytochrome c oxidase.
- Author
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Rodríguez-Roldán V, García-Heredia JM, Navarro JA, Hervás M, De la Cerda B, Molina-Heredia FP, and De la Rosa MA
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- Animals, Chemical Phenomena, Chemistry, Physical, Flavins metabolism, Humans, Kinetics, Oxidation-Reduction drug effects, Potassium Chloride pharmacology, Arabidopsis enzymology, Cytochromes c metabolism, Electron Transport Complex IV metabolism, Horses, Mitochondria enzymology
- 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. more...
- Published
- 2006
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60. 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.
- Author
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Durán RV, Hervás M, De la Cerda B, De la Rosa MA, and Navarro JA
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- Cytochromes c6 genetics, Kinetics, Models, Molecular, Oxidation-Reduction radiation effects, Plastocyanin genetics, Protein Structure, Tertiary, Synechocystis radiation effects, Thermodynamics, Cytochromes c6 metabolism, Lasers, Mutagenesis, Site-Directed, Photosystem I Protein Complex metabolism, Photosystem I Protein Complex radiation effects, Plastocyanin metabolism, Synechocystis enzymology
- 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. more...
- Published
- 2006
- Full Text
- View/download PDF
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