Identification of folding intermediates of streblin, the most stable serine protease: biophysical analysis

Kumar, Reetesh [UNESP]; Tripathi, Pinki; Moraes, Fabio Rogerio de [UNESP]; Caruso, Icaro P. [UNESP]; Jagannadham, Medicherla V.

Identification of folding intermediates of streblin, the most stable serine protease: biophysical analysis

Arquivos

WOS000332491700008.pdf (599.74 KB)

Data

2014-01-01

Autores

Kumar, Reetesh

Tripathi, Pinki

Moraes, Fabio Rogerio de

Caruso, Icaro P.

Jagannadham, Medicherla V.

Editor

Humana Press Inc

Tipo

Artigo

Direito de acesso

Acesso aberto

Resumo

Streblin, a serine proteinase from plant Streblus asper, has been used to investigate the conformational changes induced by pH, temperature, and chaotropes. The near/far UV circular dichroism activities under fluorescence emission spectroscopy and 8-aniline-1-naphthalene sulfonate (ANS) binding have been carried out to understand the unfolding of the protein in the presence of denaturants. Spectroscopic studies reveal that streblin belongs to the alpha+beta class of proteins and exhibits stability towards chemical denaturants, guanidine hydrochloride (GuHCl). The pH-induced transition of this protein is noncooperative for transition phases between pH 0.5 and 2.5 (midpoint, 1.5) and pH 2.5 and 10.0 (midpoint, 6.5). At pH 1.0 or lower, the protein unfolds to form acid-unfolded state, and for pH 7.5 and above, protein turns into an alkaline denatured state characterized by the absence of ANS binding. At pH 2.0 (1M GuHCl), streblin exists in a partially unfolded state with characteristics of amolten globule state. The protein is found to exhibit strong and predominant ANS binding. In total, six different intermediate states has been identified to show protein folding pathways.