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Titolo:
PROCESSING OF THIONIN PRECURSORS IN BARLEY LEAVES BY A VACUOLAR PROTEINASE
Autore:
ROMERO A; ALAMILLO JM; GARCIAOLMEDO F;
Indirizzi:
UNIV POLITECN MADRID,ETS INGN AGRONOMOS,DEPT BIOTECHNOL E-28040 MADRID SPAIN UNIV POLITECN MADRID,ETS INGN AGRONOMOS,DEPT BIOTECHNOL E-28040 MADRID SPAIN
Titolo Testata:
European journal of biochemistry
fascicolo: 1-2, volume: 243, anno: 1997,
pagine: 202 - 208
SICI:
0014-2956(1997)243:1-2<202:POTPIB>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
HORDEUM-VULGARE-L; DEVELOPING PUMPKIN COTYLEDONS; TOXIN ALPHA-HORDOTHIONIN; LEAF-SPECIFIC THIONINS; ASPARTIC PROTEINASE; NUCLEOTIDE-SEQUENCE; BEAN COTYLEDONS; BREFELDIN-A; IN-VITRO; MONENSIN;
Keywords:
BARLEY; PROCESSING PROTEINASE; THIONIN; VACUOLE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
51
Recensione:
Indirizzi per estratti:
Citazione:
A. Romero et al., "PROCESSING OF THIONIN PRECURSORS IN BARLEY LEAVES BY A VACUOLAR PROTEINASE", European journal of biochemistry, 243(1-2), 1997, pp. 202-208

Abstract

Thionins are synthesized as precursors with a signal peptide and a long C-terminal acidic peptide that is post-translationally processed. Afusion protein including the maltose-binding protein from Escherichiacoli (MalE), thionin DG3 from barley leaves, and its acidic C-terminal peptide has been used to obtain antibodies that recognize both domains of the precursor. In barley leaf sections, mature thionins accumulated in the vacuolar content, while the acidic peptide was not detectedin any cell fraction. Brefeldin A and monensin inhibited processing of the precursor but its export from the microsomal fraction was not inhibited. Both purified vacuoles and an acid (pH 5.5) extract from leaves processed the fusion protein into a MalE-thionin and an acidic peptide fragment. A 70-kDa proteinase that effected this cleavage was purified from the acid extract. Processing of the fusion protein by both lysed vacuoles and the purified proteinase was inhibited by Zn2+ and byCu2+, but not by inhibitors of the previously described vacuolar processing thiol or aspartic proteinases. In vivo processing of the thionin precursor in leaf sections was also inhibited by Zn2+ and Cu2+. Variants of the fusion protein with altered processing sites that represented those of thionin precursors from different taxa were readily processed ay the proteinase, whereas changing the polarity of either the C-terminal or N-terminal residues of the processing site prevented cleavage by the proteinase.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 15:05:21