Artigo
Identification of folding intermediates of streblin, the most stable serine protease: biophysical analysis
Registro en:
Applied Biochemistry And Biotechnology. Totowa: Humana Press Inc, v. 172, n. 2, p. 658-671, 2014.
0273-2289
10.1007/s12010-013-0565-8
WOS:000332491700008
WOS000332491700008.pdf
Autor
Kumar, Reetesh [UNESP]
Tripathi, Pinki
Moraes, Fabio Rogerio de [UNESP]
Caruso, Icaro P. [UNESP]
Jagannadham, Medicherla V.
Resumen
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. CSIR/CSIR DBT UGC, Government of India Banaras Hindu Univ, Inst Med Sci, Mol Biol Unit, Varanasi 221005, Uttar Pradesh, India Univ Estadual Paulista, Inst Biociencias Letras & Ciencias Exatas IBILCE, Sao Jose Do Rio Preto, SP, Brazil Univ Estadual Paulista, Inst Biociencias Letras & Ciencias Exatas IBILCE, Sao Jose Do Rio Preto, SP, Brazil