Identity of the N-terminal sequences of the three A chains of mistletoe (Viscum album L.) lectins: homology with ricin-like plant toxins and single-chain ribosome-inhibiting proteins.
Mistletoe lectin (ML) I increases the production of cytokines by mononuclear cells and has been proposed as a useful biological response modifier in the treatment of cancer. Two other lectins, ML II and ML III, have been identified in mistletoe. We report that the N-terminal sequences of the three A chains of ML I, ML II and ML III are identical, and have interesting homology with the N-terminal sequences of the A chain of ricin-like toxins and of single-chain ribosome-inhibiting proteins. In addition, the three mistletoe lectins inhibit the growth of the human tumor cell line Molt 4, ML III being the most potent. followed by ML II and ML I. This inhibition is suppressed by addition of rabbit anti-ML I antibodies to the cultured cells. The data obtained suggest that the three lectins have amino acid sequences which show extensive homology and exert very similar biological effects. They may be derived from the same precursor.
Dietrich
J B
JB
Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France.
Ribéreau-Gayon
G
G
Jung
M L
ML
Franz
H
H
Beck
J P
JP
Anton
R
R
D000595:Amino Acid Sequence; D002455:Cell Division / Q000187:drug effects; D002675:Child, Preschool; D006801:Humans; D007155:Immunologic Factors / Q000737:chemistry* / Q000633:toxicity; D015458:Leukemia, T-Cell / Q000473:pathology / Q000628:therapy; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases; D028321:Plant Preparations; D010940:Plant Proteins / Q000737:chemistry* / Q000633:toxicity; D012269:Ribosomal Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000633:toxicity; D054788:Ribosome Inactivating Proteins; D054789:Ribosome Inactivating Proteins, Type 1; D054790:Ribosome Inactivating Proteins, Type 2; D012276:Ricin / Q000737:chemistry* / Q000633:toxicity; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D014118:Toxins, Biological / Q000737:chemistry* / Q000633:toxicity; D015978:Trichosanthin / Q000737:chemistry / Q000633:toxicity; D014407:Tumor Cells, Cultured / Q000187:drug effects
D007155:Immunologic Factors; D046911:Macromolecular Substances; D028321:Plant Preparations; D010940:Plant Proteins; D012269:Ribosomal Proteins; D054789:Ribosome Inactivating Proteins, Type 1; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C488862:mistletoe lectin I; C488863:mistletoe lectin II; C488864:mistletoe lectin III; C009674:ribosome inactivating protein, Viscum; D015978:Trichosanthin; D012276:Ricin; D009699:N-Glycosyl Hydrolases; D054788:Ribosome Inactivating Proteins; C024275:pokeweed antiviral protein