Browsing by Author "Manubens, Augusto"

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    Effect of manganese on the secretion of manganese-peroxidase by the basidiomycete Ceriporiopsis subvermispora
    (2010) Mancilla, Rodrigo A.; Canessa, Paulo; Manubens, Augusto; Vicuna, Rafael
    The ligninolytic machinery of the widely used model fungus Ceriporiopsis subvermispora includes the enzymes manganese-peroxidase (MnP) and laccase (Lcs). In this work the effect of Mn(II) on the secretion of MnP was studied. Cultures grown in the absence of Mn(II) showed high levels of mnp transcripts. However, almost no MnP enzyme was detected in the extracellular medium, either by enzymatic activity assays or Western blot hybridizations. In the corresponding mycelia, immuno-electron microscopy experiments showed high levels of MnP enzyme within intracellular compartments. These results suggest that in addition to its well-known effect on transcription regulation of mnp genes, manganese influences secretion of MnP to the extracellular medium. Experiments carried out in the presence of cycloheximide confirmed that the metal is required to secrete MnP already synthesized and retained within the cell. (C) 2010 Elsevier Inc. All rights reserved.
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    Structural insights into a functional unit from an immunogenic mollusk hemocyanin
    (2024) Munoz, Sebastian M.; Vallejos-Baccelliere, Gabriel; Manubens, Augusto; Salazar, Michelle L.; Nascimento, Andrey F. Z.; Tapia-Reyes, Patricio; Meneses, Claudio; Ambrosio, Andre L. B.; Becker, Maria Ines; Guixe, Victoria; Castro-Fernandez, Victor
    Mollusk hemocyanins, among the largest known proteins, are used as immunostimulants in biomedical and clinical applications. The hemocyanin of the Chilean gastropod Concholepas concholepas (CCH) exhibits unique properties, which makes it safe and effective for human immunotherapy, as observed in animal models of bladder cancer and melanoma, and dendritical cell vaccine trials. Despite its potential, the structure and amino acid sequence of CCH remain unknown. This study reports two sequence fragments of CCH, representing three complete functional units (FUs). We also determined the high -resolution (1.5 A & ring; ) X-ray crystal structure of an "FU -g type"from the CCHB subunit. This structure enables in-depth analysis of chemical interactions at the copper -binding center and unveils an unusual, truncated N-glycosylation pattern. These features are linked to eliciting more robust immunological responses in animals, offering insights into CCH's enhanced immunostimulatory properties and opening new avenues for its potential applications in biomedical research and therapies.