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Primary structure of ω-hordothionin, a member of a novel family of thionins from barley endosperm, and its inhibition of protein synthesis in eukaryotic and prokaryotic cell-free systems.
- Source :
-
European Journal of Biochemistry . 7/1/96, Vol. 239 Issue 1, p67-73. 7p. - Publication Year :
- 1996
-
Abstract
- A new sulfur-rich basic polypeptide. so called ω-hordothionin, has been isolated from barley endosperm by extractions with NaCl and ammonium bicarbonate followed by reverse-phase high performance liquid chromatography. Purified ω-hordothionin was found to be homogeneous by SDS/polyacrylamide gel electrophoresis, N-terminal amino-acid sequencing and electrospray-ionization mass spectrometric analysis. The complete primary structure of ω-hordothionin was determined by automatic degradation of the intact molecule and peptides obtained by proteotytic cleavage. ω-hordothionin consists of a single polypeptide chain of 48 amino acids with a molecular mass of 5508 Da deduced from its amino acid sequence, which fully coincides with the 5508.2 Da determined by elcctrospray-ionization mass spectrometry. The isolated polypeptide showed a characteristic composition with a high content of basic amino acids (five arginine residues, two lysine residues and six histidine residues) and eight cysteine residues. and has strong sequence identity (66%) with the sorghum SIα1 α-amylase inhibitor. ω-hordothionin. like γ-hordothionin. exhibited translation inhibitory activity on both cukaryotic cell-free systems from mammalian (rat liver and rabbit reticulocyte lysates) and prokaryotic cell-free systems (Escherichia coli). However, in contrast to γ-hordothiomn, ω-hordothionin did not inhibit plant systems such as Triticum aestivum, Cucumis sativus, Vicia sativa and Hordeum vulgare. ;γ-hordothionin also inhibited the α-amylase activity from human saliva, while ω-hordothionin and the other different genetic variants of thionins, α- hordothionin and β-hordothionin. failed to show any inhibitory effect. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00142956
- Volume :
- 239
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- European Journal of Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 15799510
- Full Text :
- https://doi.org/10.1111/j.1432-1033.1996.0067u.x