The Recombinant Sea Urchin Immune Effector Protein, rSpTransformer-E1, Binds to Phosphatidic Acid and Deforms Membranes.

The purple sea urchin, , possesses a sophisticated innate immune system that functions without adaptive capabilities and responds to pathogens effectively by expressing the highly diverse gene family (formerly the gene family). The swift gene expression response and the sequence diversity of cDNAs suggest that the encoded proteins have immune functions. Individual sea urchins can express up to 260 distinct SpTransformer proteins, and their diversity suggests that different versions may have different functions.

Membrane phase characteristics control NA-CATH activity.

Our studies presented in this report focus on the behavior of NA-CATH, an α-helical cathelicidin antimicrobial peptide, originally discovered in the Naja atra snake. It has demonstrated high potency against gram-positive and gram-negative bacteria with minimal hemolysis. Here we examine the kinetics, behaviors and potential mechanisms of the peptide in the presence of membrane liposome, modeling Escherichia coli, whose membrane exhibits distinct lipid phases.

The structure and behavior of the NA-CATH antimicrobial peptide with liposomes.

Naja atra cathelicidin (NA-CATH) is a 34-amino acid highly cationic peptide identified in Chinese cobras to possess potent toxicity against gram-negative and gram-positive bacteria and low toxicity against host cells. Here, we report the NMR solution structure of the full-length NA-CATH peptide and its interaction with liposomes. The structure shows a well-defined α-helix between residues Phe3 to Lys23, on which one surface is lined by the side-chains of one arginine and 11 lysine residues, while the other side is populated by hydrophobic residues.

Long-term reduction in poly(dimethylsiloxane) surface hydrophobicity via cold-plasma treatments.

Poly(dimethylsiloxane), PDMS, a versatile elastomer, is the polymer of choice for microfluidic systems. It is inexpensive, relatively easy to pattern, and permeable to oxygen. Unmodified PDMS is highly hydrophobic.