Complete amino acid sequence of the A chain of mistletoe lectin I

Abstract
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 analysis and MALDIMS. The data obtained show a great homology with the chains of ribosome‐inactivating proteins such as ricin and abrin with 111 (abrin‐a) and 103 (ricin‐D) amino acid residues conserved, respectively. The knowledge of the primary structure of MLA will have a fundamental impact on elucidating the biological function of medically applied mistletoe lectins on a molecular basis.