Structural and enzymatic characterization of PeruvianinI, the first germin-like protein with proteolytic activity.
Int J Biol Macromol
; 126: 1167-1176, 2019 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-30625353
ABSTRACT
The germin-like protein (GLP) purified from Thevetia peruviana, Peruvianin-I, is the only one described as having proteolytic activity. Therefore, the goal of this study was to investigate the structural features responsible for its enzymatic activity. Although the amino acid sequence of Peruvianin-I showed high identity with other GLPs, it exhibited punctual mutations, which were responsible for the absence of oxalate oxidase activity. The phylogenetic analysis showed that Peruvianin-I does not belong to any classification of GLP subfamilies. Moreover, Peruvianin-I contains a catalytic triad found in all plant cysteine peptidases. Molecular docking simulations confirmed the role of the catalytic triad in its proteolytic activity. Synchrotron radiation circular dichroism assays confirmed that Peruvianin-I was stable at pH ranging from 5.0 to 8.0 and that it presented significant structural changes only above 60⯰C. The addition of iodoacetamide caused changes in its native conformation, but only a slight effect was observed after adding a reducing agent. This study reports an unusual protein with germin-like structure, lacking typical oxalate oxidase activity. Instead, the proteolytic activity observed suggests that the protein is a cysteine peptidase. These structural peculiarities make PeruvianinI an interesting model for further understanding of the action of laticifer fluids in plant defense.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
/
Glicoproteínas
/
Thevetia
/
Proteólise
Idioma:
En
Revista:
Int J Biol Macromol
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Brasil