Wheat ribosome-inactivating proteins: Seed and leaf forms with different specificities and cofactor requirements

• Published in: Planta Vol. 197; no. 4; pp. 633 - 640
• Main Authors: Massiah, A.J, Hartley, M.R. (Warwick Univ., Coventry (United Kingdom). Dept. of Biological Sciences)
• Format: Journal Article
• Language: English
• Published: Berlin Springer-Verlag 1995; Springer
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ADENOSINE TRIPHOSPHATE; Adenosine Triphosphate - metabolism; ADENOSINTRIFOSFATO; Animals; Antivirals; ARN; Barley; Base Sequence; Biological and medical sciences; Biotechnology; Corn; Electrophoresis, Gel, Two-Dimensional; Endosperm; ENZIMAS; ENZYME; ENZYMES; ENZYMIC ACTIVITY; FEUILLE; Fundamental and applied biological sciences. Psychology; Gelelektrophorese; Gels; GRAINE; HOJAS; IMMUNOLOGICAL TECHNIQUES; ISOENZIMAS; ISOENZYME; ISOENZYMES; Isoenzymes - isolation & purification; Isoenzymes - metabolism; LEAVES; Metabolism; Molecular Sequence Data; N-Glycosyl Hydrolases - isolation & purification; N-Glycosyl Hydrolases - metabolism; NUCLEOTIDE SEQUENCE; PEPTIDE; PEPTIDES; PEPTIDOS; Pflanzenbau; Pflanzenphysiologie; Plant Leaves - enzymology; Plant physiology and development; Plant Proteins - immunology; Plant Proteins - isolation & purification; Plant Proteins - metabolism; PLANT TISSUES; Plants; Polypeptid; PROTEINAS; PROTEINE; PROTEINS; Rabbits; Reticulocytes; RIBOSOMAS; RIBOSOME; Ribosome Inactivating Proteins; Ribosome Inactivating Proteins, Type 1; RIBOSOMES; Ribosomes - metabolism; RNA; RNA, Ribosomal - metabolism; SACCHAROMYCES CEREVISIAE; SECUENCIA NUCLEOTIDICA; SEEDS; Seeds - enzymology; SEMILLA; SEQUENCE NUCLEOTIDIQUE; Substrate Specificity; Substratspezifitaet; TECHNIQUE IMMUNOLOGIQUE; TECNICAS INMUNOLOGICAS; TEJIDOS VEGETALES; TISSU VEGETAL; Triticum - enzymology; TRITICUM AESTIVUM; Yeasts; Monocotyledones; Seeds; Purification; rRNA N-glycosidase; Enzyme; Isozyme; Plant leaf; Cofactor; Cereal crop; Characterization; Enzymatic activity; Gramineae; Glycosidases; Substrate specificity; Angiospermae; Hydrolases; N-Glycosidases; Spermatophyta; Triticum aestivum
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/BF00191571

Distinct forms of ribosome-inactivating proteins were purified from wheat (Triticum aestivum L.) germ and leaves and termed tritin-S and tritin-L, respectively. These differ in size and charge and are antigenically unrelated. They are both RNA N-glycosidases which act on 26S rRNA in native yeast (Saccharomyces cerevisiae) ribosomes by the removal of A3024 located in a universally conserved sequence in domain VII which has previously been identified as the site of action of ricin A-chain. Tritin-S and tritin-L differ in both their ribosome substrate specificities and cofactor requirements. Tritin-S shows only barely detectable activity on ribosomes from the endosperm, its tissue of synthesis, whereas tritin-L is highly active on leaf ribosomes. Additionally, tritin-S is inactive on wheat germ, tobacco leaf and Escherichia coli ribosomes but active on rabbit reticulocyte and yeast ribosomes. Tritin-L is active on ribosomes from all of the above sources. Tritin-S, unlike tritin-L shows a marked requirement for ATP in its action.