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    Estudos da relação estrutura-atividade da Rondonina e análogos
    (Universidade Federal de São Paulo, 2022-04-27) Rocha, Ana Laís Bignotto da [UNIFESP]; Oliveira Junior, Vani Xavier de; Silva Junior, Pedro Ismael da; http://lattes.cnpq.br/7158586957386749; http://lattes.cnpq.br/8202238208943023; http://lattes.cnpq.br/7431823973508374
    Introduction: Rondonin is a native AMP, isolated from the spider Acanthoscurria rondoniae's plasm , presenting a molecular mass of 1236,78 Da (UniProt acession number B3EWP8), features antifungal activity, on plasmatic membrane inside targets, and tends not to structure itself. Objectives: The studies tried to stabilish the relation between the structure and activity of the synthesized analogs from native Rondonin. Peptides were projected from the studie of N and C terminus modification, charge increment – trough single arginine substitutions - (Arg-scan) -, and double, besides tryptophan punctual substitution and glycine deletion. These changes, in the molecular design, were elaborated with the goal of studying possible improvement in antimicrobial, antifungal; antisporulatory;hemolytic; spores germination influence and stability to enzymatic degradation. Methods: Analogues were synthesized in solid phase synthesis strategy trough High Performance Liquid Chromatography.and characterized through Mass Spectrometry (LC/ESI-MS). Antimicrobial, antisporulatory, antifungal and antigermintaive studies were determined through growth inhibition assay, in liquid medium conformational study was realized with Circular Dichroism (CD) spectrometry in four mediums. Results: From the information that Rondonin acts in internal targets was possible to develop molecules with sequential arginine substitutions, which may generate a charge increment added to the amphipaticity of designed analogues. This simple premise was established with the goal to build molecules with greater capacity of interaction with negatively charged targets, such as ribosomes, Golgi apparatus mitochondria DNA and RNAs. Secondary structures show tendency to randomize. Peptides do not show hemolysis in inhibitory concentrations. Stability times of studied peptides were compatible with stability of commercial composts with oral pathway administration, in concentrastions without toxicity, the molecule with greater stability was analogue 8. Synthesis of developed analogues, that has arginine substitutions in the hydrophobic central moiety, showed improvement the antifungal activity, that suggests that charge increase and amphipaticity alteration were very important for analogues activities, the molecule with the best antifungal activity was analogue analogue 10. However, analogues did not show activities against Gram-positive and Gram-negative bacteria under the tested concentrations. Nevertheless sporulation assays realized with filamentous fungus showed important inhibition activities of conidia formation. The same activity was not found on the 8 pharmaceutics tested for comparative ends. The peptides that showed better antisporulatory MIC values against Penicilium expansum – Bread isolated was analogue 10 at 0,7µmol.L-1 concentration. Antigerminative activities were obtained from mature spores of P. expansum in rich medium (NaCl 45 g.L-1) and poor medium (distilled water) analogue 2, analogue 9 and analogue 18 showed concentration of antigermination 28 µmol.L-1 much smaller than the control made through Hydrogen peroxide 15 g.L-1. Conclusion: Structural modifications from linear Rondonin analogues sequence changes were fundamental for increased antifungal activity, against filamentous fungi and several species of Candida genus. Besides sporulation assays, in filamentous fungi, showed new possibilities for research development about fungal life cycle analysis reinforcing the utility of AMPs as molecular engineering tools. The design based in a simple premise of analogues production developed a spectrum of peptides with multiple and potent activities. These results provide information about the structure activity relationship for the design of new analogues with antifungal activitiy.