Purification and amino acid sequence of basic protein I, a lysine-49-phospholipase A 2 with low activity, from the venom of Trimeresurus flavoviridis (Habu snake)

Abstract

K. Yoshizumi, S.-Y. Liu, T. Miyata, S. Saita, M. Ohno, S. Iwanaga and H. Kihara. Purification and amino acid sequence of basic protein I, a lysine-49-phospholipase A 2 with low activity, from the venom of Trimeresurus flavoviridis (Habu snake). Toxicon 28, 43–54, 1990.—A basic protein (pI 10.2), named basic protein I, was purified to homogeneity from the venom of Trimeresurus flavoviridis (Habu snake) after four chromatographic steps. The amino acid sequence of this protein was determined by sequencing the S-pyridylethylated derivative of the protein and its peptides produced by chemical (cyanogen bromide and formic acid) and enzymatic (chymotrypsin, Achromobacter protease I, and Staphylococcus aureus V8 protease) cleavages. The protein consisted of 122 amino acid residues and was similar in sequence to phospholipases A 2 from the venoms of crotalid and viperid snakes. A most striking feature of this protein is that aspartic acid at the 49th position common in phospholipases A 2 is replaced by lysine. When the protein acted on 1-palmitoyl-2-oleoyl- sn-glycero-3-phosphorylcholine, oleic acid was preferentially released, indicating that the protein has phospholipase A 2 activity. Its molar activity toward 1,2-dilauroly- sn-glycero-3-phosphorylcholine, however, was 1.5% that of T. flavoviridis phospholipase A 2 isolated previously. The fact that both affinity to Ca 2+ and reactivity to p-bromophenacyl bromide of basic protein I are approximately one order of magnitude lower than those of T. flavoviridis phospholipase A 2 might explain the low activity of basic protein I.