SEQUENCE-ANALYSIS AND STRUCTURAL FEATURES OF THE LARGEST KNOWN PROTAMINE ISOLATED FROM THE SPERM OF THE ARCHAEOGASTROPOD MONODONTA-TURBINATA

Protamine of the archaeogastropod mollusc Monodonta turbinata has been isolated and characterized. With a mass of 13,476 Da, it is the large st known protamine. Amino acid sequence of this protamine (106 residue s) was established from data provided by automated sequence analysis a nd mass spectrometry of the protein and of its fragments. The primary structure of the NH2-terminal region exhibits repetitive sequence moti fs ''Basic-Ser'' (mainly R-S) and both central and COOH-terminal regio ns are composed by arginine clusters. The amino acid sequence of Monod onta turbinata protamine shows structural similarities with other prot amines from invertebrates and from birds and mammals.