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Structure-guided identification of function: role of Capsicum annuum vicilin during oxidative stress.
- Source :
-
The Biochemical journal [Biochem J] 2018 Oct 09; Vol. 475 (19), pp. 3057-3071. Date of Electronic Publication: 2018 Oct 09. - Publication Year :
- 2018
-
Abstract
- Proteins belonging to cupin superfamily are known to have critical and diverse physiological functions. However, 7S globulins family, which is also a part of cupin superfamily, were undermined as only seed storage proteins. Structure determination of native protein - Vic&#95;CAPAN from Capsicum annuum - was carried out, and its physiological functions were explored after purifying the protein by ammonium sulfate precipitation followed by size exclusion chromatography. The crystal structure of vicilin determined at 2.16 Å resolution revealed two monomers per asymmetric unit which are juxtaposed orthogonal with each other. Vic&#95;CAPAN consists predominately of β-sheets that folds to form a β-barrel structure commonly called cupin fold. Each monomer of Vic&#95;CAPAN consists of two cupin fold domains, N-terminal and C-terminal, which accommodate two different ligands. A bound ligand was identified at the C-terminal cupin fold in the site presumably conserved for metabolites in the crystal structure. The ligand was confirmed to be salicylic acid through mass spectrometric analysis. A copper-binding site was further observed near the conserved ligand-binding pocket, suggesting possible superoxide dismutase activity of Vic&#95;CAPAN which was subsequently confirmed biochemically. Vicilins from other sources did not exhibit this activity indicating functional specificity of Vic&#95;CAPAN. Discovery of bound salicylic acid, which is a known regulator of antioxidant pathway, and revelation of superoxide dismutase activity suggest that Vic&#95;CAPAN has an important role during oxidative stress. As salicylic acid changes the redox state of cell, it may act as a downstream signal for various pathways involved in plant biotic and abiotic stress rescue.<br /> (© 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)
- Subjects :
- Amino Acid Sequence
Binding Sites physiology
Crystallization
Plant Extracts genetics
Protein Structure, Secondary
Seed Storage Proteins genetics
Seeds
Capsicum
Oxidative Stress physiology
Plant Extracts chemistry
Plant Extracts metabolism
Seed Storage Proteins chemistry
Seed Storage Proteins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1470-8728
- Volume :
- 475
- Issue :
- 19
- Database :
- MEDLINE
- Journal :
- The Biochemical journal
- Publication Type :
- Academic Journal
- Accession number :
- 30181145
- Full Text :
- https://doi.org/10.1042/BCJ20180520