Cloning and expression of mistletoe lectin III B-subunit.
Aqueous extracts of mistletoe (Viscum album L.) contain toxic proteins (lectins) MLI (viscumin), MLII, and MLIII. We previously cloned the gene encoding MLIII precursor. In the present study, a gene fragment encoding the carbohydrate-binding subunit of mistletoe toxic lectin MLIII was cloned and expressed in Escherichia coli cells. The structure and immunochemical properties of recombinant MLIII B-subunit were investigated using a panel of monoclonal antibodies against ML-toxins. Sugar-binding activity of recombinant MLIII B-subunit was determined by ELISA. Amino acid sequence analysis of the cloned MLIII compared with known mistletoe toxins and other ribosome-inactivating type II proteins (ricin, abrin a, and nigrin b B-subunits) revealed essential features of the recombinant MLIIIB primary structure that could determine sugar specificity of the lectin as well as immunomodulating and anti-tumor properties of mistletoe extracts.
Pevzner
I B
IB
Faculty of Biology, Lomonosov Moscow State University, Moscow 119899, Russia.
Agapov
I I
II
Pfueller
U
U
Pfueller
K
K
Maluchenko
N V
NV
Moisenovich
M M
MM
Tonevitsky
A G
AG
Kirpichnikov
M P
MP
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression; D008969:Molecular Sequence Data; D028321:Plant Preparations / Q000276:immunology; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D011994:Recombinant Proteins / Q000096:biosynthesis; D054788:Ribosome Inactivating Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D016415:Sequence Alignment; D014118:Toxins, Biological / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology; D028182:Viscum album / Q000235:genetics
D028321:Plant Preparations; D010940:Plant Proteins; D011994:Recombinant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C488864:mistletoe lectin III; C009674:ribosome inactivating protein, Viscum; D054788:Ribosome Inactivating Proteins