Purification and Pore Forming Activity of Two Hydrophobic Polypeptides from the Secretion of the Red Sea Moses Sole (Pardachirus marmoratus)

摘要

A new column chromatography procedure, based on ion exchange, chromato-focusing and reverse phase HPLC was employed to isolate the two main protaeceous, toxic, cytolytic, pore forming factors from the secretion of the Red Sea Moses sole Pardachirus marmoratus. Pardaxin I, comprising 10% of the gland secretion proteins, was shown to be 5-10 times more toxic, cytolotic and active in membrane pore formation that pardaxin II (8% of gland secretion proteins). Gel-electrophoresis, amino acid analysis and N-terminal amino acid sequence reveals a high degree of homogeneity and resemblance between the two toxins. They are in aspartic, serine, glycine, alanine, and devoid of arginine, typrosine, and tryptophan. Their N-terminal was found to be NH2-Gly-Phe-Phe. Their hydrophobicity is evident from the chromatographic behavior on a hydrophobic resin, presence of nine successive hydrophobic residues on the NH2-terminal and a decrease in drop size during elution of active fractions during chromatographic purification. The minimal molecular weight of Pardaxin I is about 3500 as determined by SDS gel electrophoresis and amino acid analyses. It is composed of 35 amino acids and is free of carbohydrate and sialic acid residues. Mass spectrometry of the ethyl acetate extract of the gland secretion and purified toxin reveals the presence of sterols in the secretion but their absence in the purified toxins. Pardaxin I was iodinated without affecting its chemical and pore forming properties.