Dendropsophin 1, a novel antimicrobial peptide from the skin secretion of the endemic Colombian frog Dendropsophus columbianus.

In efforts to find new antimicrobial peptides (AMPs), we studied the skin secretion of the endemic Colombian frog Dendropsophus columbianus belonging to a genus that has not been investigated previously. From HPLC-fractionated secretion, we identified one peptide with slightly antibacterial activity. Its peptide sequence showed no sequence similarity to current annotated peptides. We named this novel peptide dendropsophin 1 (Dc1). Afterward, two analogues were designed (Dc1.1 and Dc1.2) to improve the cationic and amphipathic features. Then, their antiproliferative and cytotoxic properties were evaluated against several pathogens including bacteria, fungi, protozoa and also mammalian cells. Dc1 and its two analogues exhibited moderate antibacterial activities and no hemolytic and cytotoxic effects on mammalian cells. Analogue Dc1.2 showed slightly improved antibacterial properties. Their secondary structures were characterised using CD spectroscopy and Dc1.2 displayed a higher α-helix content and thermal stability compared to Dc1 and Dc1.1 in hydrophobic experimental conditions.

Dendropsophin 1, a novel antimicrobial peptide from the skin secretion of the endemic Colombian frog Dendropsophus columbianus

In efforts to find new antimicrobial peptides (AMPs), we studied the skin secretion of the endemic Colombian frog Dendropsophus columbianus belonging to a genus that has not been investigated previously. From HPLC-fractionated secretion, we identified one peptide with slightly antibacterial activity. Its peptide sequence showed no sequence similarity to current annotated peptides. We named this novel peptide dendropsophin 1 (Dc1). Afterward, two analogues were designed (Dc1.1 and Dc1.2) to improve the cationic and amphipathic features. Then, their antiproliferative and cytotoxic properties were evaluated against several pathogens including bacteria, fungi, protozoa and also mammalian cells. Dc1 and its two analogues exhibited moderate antibacterial activities and no hemolytic and cytotoxic effects on mammalian cells. Analogue Dc1.2 showed slightly improved antibacterial properties. Their secondary structures were characterised using CD spectroscopy and Dc1.2 displayed a higher -helix content and thermal stability compared to Dc1 and Dc1.1 in hydrophobic experimental conditions.

Dendropsophin 1, a novel antimicrobial peptide from the skin secretion of the endemic Colombian frog Dendropsophus columbianus

In efforts to find new antimicrobial peptides (AMPs), we studied the skin secretion of the endemic Colombian frog Dendropsophus columbianus belonging to a genus that has not been investigated previously. From HPLC-fractionated secretion, we identified one peptide with slightly antibacterial activity. Its peptide sequence showed no sequence similarity to current annotated peptides. We named this novel peptide dendropsophin 1 (Dc1). Afterward, two analogues were designed (Dc1.1 and Dc1.2) to improve the cationic and amphipathic features. Then, their antiproliferative and cytotoxic properties were evaluated against several pathogens including bacteria, fungi, protozoa and also mammalian cells. Dc1 and its two analogues exhibited moderate antibacterial activities and no hemolytic and cytotoxic effects on mammalian cells. Analogue Dc1.2 showed slightly improved antibacterial properties. Their secondary structures were characterised using CD spectroscopy and Dc1.2 displayed a higher -helix content and thermal stability compared to Dc1 and Dc1.1 in hydrophobic experimental conditions.

Biochemical and Structural Characterization of Amy1: An Alpha-Amylase from Cryptococcus flavus Expressed in Saccharomyces cerevisiae.

An extracellular alpha-amylase (Amy1) whose gene from Cryptococcus flavus was previously expressed in Saccharomyces cerevisiae was purified to homogeneity (67 kDa) by ion-exchange and molecular exclusion chromatography. The enzyme was activated by NH(4) (+) and inhibited by Cu(+2) and Hg(+2). Significant biochemical and structural discrepancies between wild-type and recombinant α-amylase with respect to K(m) values, enzyme specificity, and secondary structure content were found. Far-UV CD spectra analysis at pH 7.0 revealed the high thermal stability of both proteins and the difference in folding pattern of Amy1 compared with wild-type amylase from C. flavus, which reflected in decrease (10-fold) of enzymatic activity of recombinant protein. Despite the differences, the highest activity of Amy1 towards soluble starch, amylopectin, and amylase, in contrast with the lowest activity of Amy1(w), points to this protein as being of paramount biotechnological importance with many applications ranging from food industry to the production of biofuels.