COMPLETE AMINO-ACID-SEQUENCE OF THE A-CHAIN OF MISTLETOE LECTIN-I

The complete amino acid sequence of the A chain of mistletoe lectin I was determined via Edman degradation sequencing of the N-terminus and tryptic and endoproteinase Asp-N overlapping fragments, amino acid ana lysis and MALDI-MS. The data obtained show a great homology with the c hains of ribosome-inactivating proteins such as ricin and abrin with 1 11 (abrin-a) and 103 (ricin-D) amino acid residues conserved, respecti vely. The knowledge of the primary structure of MLA will have a fundam ental impact on elucidating the biological function of medically appli ed mistletoe lectins on a molecular basis.