A new gene encoding the ribosome-inactivating protein from mistletoe extracts.
Extracts from mistletoe (Viscum album L.) contain three main toxic proteins--the lectins MLI (also known as viscumin), MLII and MLIII. A catalytic subunit of the mistletoe plant toxic lectin MLIII has been cloned and expressed in Escherichia coli cells. The structure and immunochemical properties of recombinant MLIII A-subunit were investigated using a panel of monoclonal antibodies against ML-toxins. Ribosome-inactivating activity of the recombinant MLIII A-subunit was determined in a cell-free system exhibiting inhibition of endogenous protein synthesis. The comparative analysis of nucleotide and deduced amino acid sequences of the cloned MLIII A and the native MLI A-subunits was performed, revealing the main differences in the primary structure of these proteins. Antigenicity analysis of the MLIII A-subunit has revealed a new epitope D179-E184 that is not present in viscumin. The role of toxic lectins with respect to the immunological properties of mistletoe extracts is discussed.
Tonevitsky
Alexander G
AG
Biology Department, M.V. Lomonosov Moscow State University, Vorobyevy Gori, Moscow, Russia.
Agapov
Igor I
II
Pevzner
Irina B
IB
Maluchenko
Nataliya V
NV
Moisenovich
Mikhail M
MM
Palmer
Rex A
RA
Yurkova
M
M
Pfüller
Karola
K
Pfüller
Uwe
U
D001483:Base Sequence; D002474:Cell-Free System; D003001:Cloning, Molecular; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics*; D037102:Lectins / Q000737:chemistry* / Q000235:genetics*; D014784:Mistletoe / Q000737:chemistry* / Q000235:genetics*; D008969:Molecular Sequence Data; D010936:Plant Extracts / Q000737:chemistry; D028321:Plant Preparations / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics*; D011994:Recombinant Proteins / Q000032:analysis / Q000096:biosynthesis; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological / Q000737:chemistry* / Q000235:genetics*
D017931:DNA Primers; D000939:Epitopes; D037102:Lectins; D010936:Plant Extracts; D028321:Plant Preparations; D010940:Plant Proteins; D011994:Recombinant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C009674:ribosome inactivating protein, Viscum