R. Melero

Publications (8)6.41 Total impact

• Article: Electron microscopy studies on the quaternary structure of p53 reveal different binding modes for p53 tetramers in complex with DNA

  R. Melero, S. Rajagopalan, M. Lazaro, A. C. Joerger, T. Brandt, D. B. Veprintsev, G. Lasso, D. Gil, S. H. Scheres, J. M. Carazo, A. R. Fersht, M. Valle
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  ABSTRACT: The multidomain homotetrameric tumor suppressor p53 has two modes of binding dsDNA that are thought to be responsible for scanning and recognizing specific response elements (REs). The C termini bind nonspecifically to dsDNA. The four DNA-binding domains (DBDs) bind REs that have two symmetric 10 base-pair sequences. p53 bound to a 20-bp RE has the DBDs enveloping the DNA, which is in the center of the molecule surrounded by linker sequences to the tetramerization domain (Tet). We investigated by electron microscopy structures of p53 bound to DNA sequences consisting of a 20-bp RE with either 12 or 20 bp nonspecific extensions on either end. We found a variety of structures that give clues to recognition and scanning mechanisms. The 44- and 60-bp sequences gave rise to three and four classes of structures, respectively. One was similar to the known 20-bp structure, but the DBDs in the other classes were loosely arranged and incompatible with specific DNA recognition. Some of the complexes had density c
  Proc Natl Acad Sci U S A. 01/2011; 108:557-62.
• Source

  Available from: Carlos Oscar S. Sorzano

  Conference Proceeding: Electric-potential reconstructions of single particles using L2-gradient flows

  Ming Li, Guoliang Xu, C.O.S. Sorzano, R. Melero, C. Bajaj
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  ABSTRACT: In this paper, we present a stable, reliable and robust method for reconstructing a three dimensional density function from a set of two dimensional electron microscopy images. By minimizing an energy functional consisting of a fidelity term and a regularization term, a L²-gradient flow is derived. The flow is integrated by a finite element method in the spatial direction and an explicit Euler scheme in temporal direction. The experimental results show that the proposed method is efficient and effective.
  Biomedical Engineering and Informatics (BMEI), 2010 3rd International Conference on; 11/2010
• Source

  Available from: J R Bilbao-Castro

  Article: A clustering approach to multireference alignment of single-particle projections in electron microscopy.

  C O S Sorzano, J R Bilbao-Castro, Y Shkolnisky, M Alcorlo, R Melero, G Caffarena-Fernández, M Li, G Xu, R Marabini, J M Carazo
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  ABSTRACT: Two-dimensional analysis of projections of single-particles acquired by an electron microscope is a useful tool to help identifying the different kinds of projections present in a dataset and their different projection directions. Such analysis is also useful to distinguish between different kinds of particles or different particle conformations. In this paper we introduce a new algorithm for performing two-dimensional multireference alignment and classification that is based on a Hierarchical clustering approach using correntropy (instead of the more traditional correlation) and a modified criterion for the definition of the clusters specially suited for cases in which the Signal-to-Noise Ratio of the differences between classes is low. We show that our algorithm offers an improved sensitivity over current methods in use for distinguishing between different projection orientations and different particle conformations. This algorithm is publicly available through the software package Xmipp.
  Journal of Structural Biology 03/2010; 171(2):197-206. · 3.41 Impact Factor
• Article: Quaternary structures of tumor suppressor p53 and a specific p53–DNA complex

  H. Tidow, R. Melero, E. Mylonas, S. Freund, J. G. Grossmann, J. M. Carazo, D. I. Svergun, M. Valle, A. R. Fersht
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  ABSTRACT: Quaternary structures of tumor suppressor p53 and a specific p53–DNA complex
  Proceedings of the National Academy of Sciences. 01/2007; 104:12324.
• Article: [Progressive deterioration in an elderly patient].

  R Melero, M Adrados, I Fuentes, R Carrillo, J Casado, J Hurtado, C Caramelo, J Martín
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  ABSTRACT: Vasculitis is diagnosed with increasing frequency in the elderly. We hereby present the case of an 84-year-old male, who had weight loss, low-degree fever, anemia and epigastric pain. After 14 days of study with the tentative diagnosis of digestive neoplasia, a progressive renal insufficiency was detected. This clinical picture was secondary to ANCA-positive vasculitis. The case poses the differential diagnosis of non-oliguric acute renal failure (FRA) in elder people and the systematics of the study of renal insufficiency in individuals with previously unknown renal function. Also, this patient's history emphasizes the importance of acute deterioration of renal function as a guiding symptom for orienting the interpretation of clinical data. In the present case, a diagnostic hypothesis based only in the pursue of an occult digestive tumor misguided the attention from the main cause of the disease.
  Nefrologia: publicacion oficial de la Sociedad Espanola Nefrologia 02/2004; 24 Suppl 3:64-7. · 1.00 Impact Factor
• Article: [Structural changes and vascular calcifications in uremia].

  C Caramelo, M Goicoechea, M Albalate, L Nieto, R Melero, J R Berlanga, M D López, F González Pacheco, B Marrón, M V Alvarez Arroyo, M A Castilla, S Yagüe, J J Deudero, A Ortiz
  Nefrologia: publicacion oficial de la Sociedad Espanola Nefrologia 02/2001; 21(6):538-47. · 1.00 Impact Factor
• Article: [Experience with sevelamer in peritoneal dialysis].

  A Ortiz, F Ríos, R Melero, A Reyero, R Gazapo, S Casado
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  ABSTRACT: Sevelamer is a non-absorbable phosphorus chelator that is not a source of aluminium, calcium or base. The clinical experience with sevelamer in peritoneal dialysis and in daily clinical practice is scarce. The aim of this study is to evaluate the results of therapy of hyperphosphoremia with sevelamer on serum phosphorus and phosphorus chelators requirements, in a peritoneal dialysis clinical practice. Sevalamer 400 mg was prescribed to peritoneal dialysis patients with hyperphosphoremia who were treated with aluminium hydroxide or with calcium salts in the absence of hypocalcemia. Fourteen patients completed 12 months of therapy. The initial sevelamer dose was 2,280 +/- 760 mg/day, and was increased to 2,760 +/- 1,160 mg/day at 12 months. At 12 months no patient was on aluminium salts and calcium salts had been significantly reduced. Phosphoremia (5.9 +/- 0.6 to 5.0 +/- 1.4 mg/dL, p = 0.049), calcium-phosphorus product (59.8 +/- 5.8 to 48.6 +/- 12.5 mg2/dL2, p = 0.01) and serum cholesterol (191 +/- 29 to 167 +/- 33 mg/dL, p = 0.02) decreased at 12 months. No significant changes were observed in serum triglycerides, total CO2 or PTH. Serum alkaline phosphatase increased at 6 months, but values returned to normal at 12 months. No changes were observed in serum gamma-glutamyl-transpeptidase. Five patients were started on 1.25 (OH)2 vitamin D therapy. In peritoneal dialysis patients, sevelamer allows a satisfactory control of serum phosphorus levels and calcium-phosphorus product, while decreasing the amount of aluminium and calcium salts prescribed.
  Nefrologia: publicacion oficial de la Sociedad Espanola Nefrologia 23(5):432-6. · 1.00 Impact Factor
• Article: From the Cover: Quaternary structures of tumor suppressor p53 and a specific p53 DNA complex.

  H. Tidow, R. Melero, E. Mylonas, S M Freund, J.G. Grossmann, J M Carazo, D.I. Svergun, M Valle, A R Fersht
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  ABSTRACT: Journal article
  Proc. Nat. Acad. Sci. USA 104(2007)30,12324-12329.