Browsing by Author "Liscano, Yamil"
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Item Increases in hydrophilicity and charge on the polar face of alyteserin 1c helix change its selectivity towards gram-positive bacteria(MDPI AG, 2019-11-27) Liscano, Yamil; Salamanca, Constain H.; Vargas, Lina; Cantor, Stefania; Laverde Rojas, Valentina; Oñate Garzón, JoséRecently, resistance of pathogens towards conventional antibiotics has increased, representing a threat to public health globally. As part of the fight against this, studies on alternative antibiotics such as antimicrobial peptides have been performed, and it has been shown that their sequence and structure are closely related to their antimicrobial activity. Against this background, we here evaluated the antibacterial activity of two peptides developed by solid-phase synthesis, Alyteserin 1c (WT) and its mutant derivative (ΔM), which shows increased net charge and reduced hydrophobicity. These structural characteristics were modified as a result of amino acid substitutions on the polar face of the WT helix. The minimum inhibitory concentration (MIC) of both peptides was obtained in Gram-positive and Gram-negative bacteria. The results showed that the rational substitutions of the amino acids increased the activity in Gram-positive bacteria, especially against Staphylococcus aureus, for which the MIC was one-third of that for the WT analog. In contrast to the case for Gram-positive bacteria, these substitutions decreased activity against Gram-negative bacteria, especially in Escherichia coli, for which the MIC was eight-fold higher than that exhibited by the WT peptide. To understand this, models of the peptide behavior upon interacting with membranes of E. coli and S. aureus created using molecular dynamics were studied and it was determined that the helical stability of the peptide is indispensable for antimicrobial activity. The hydrogen bonds between the His20 of the peptides and the phospholipids of the membranes should modulate the selectivity associated with structural stability at the carboxy-terminal region of the peptides.Item Potencial farmacológico in silico de péptidos obtenidos por hidrolisis enzimática de la proteína de quinua(Universidad Santiago de Cali, 2024) Ruiz Beltrán, Daniela; Uzuriaga Perlaza, Laura Mercedes; Liscano, Yamil; Oñate, JosePeptides, organic compounds formed by the union of amino acids, are highly valued in the pharmaceutical field due to their high specificity and low toxicity. However, in vivo research with peptides can be costly and slow. In contrast, in silico research offers significant savings in time and costs, allowing a broader search and quick analysis of possible biological activities. The enzymatic hydrolysis of proteins, a process that breaks down proteins into amino acids to reach peptides, is fundamental in this field. Quinoa, a pseudocereal native to the Andes with a high protein content, has been the subject of research for the development of new drugs. Bioinformatics tools, which predict and analyze the breakdown of chemical bonds in biological molecules, are increasingly used to design and select peptides with biological activities. Using the NCBI biology tool, the sequence of the quinoa protein was obtained and bioactive predictions were made in 5119 peptidic sequences obtained by hydrolysis of the actinidin enzyme. The bioactive peptides found can be the basis for developing new drugs to prevent and treat microbial diseases and cancer, thus improving the quality of life of people