Biophysical insight into structure-function relation of Allium sativum Protease Inhibitor by thermal, chemical and pH-induced modulation using comprehensive spectroscopic analysis

Tooba Naz Shamsi, Romana Parveen, Huma Naz, Md Anzarul Haque, Sadaf Fatima

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

In this study, we have analyzed the structural and functional changes in the nature of Allium sativum Protease Inhibitor (ASPI) on undergoing various denaturation with variable range of pH, temperature and urea (at pH 8.2). ASPI being anti-tryptic in nature has native molecular mass of ∼15 kDa. The conformational stability, functional parameters and their correlation were estimated under different conditions using circular dichroism, fluorescence and activity measurements. ASPI was found to fall in belongs to α+β protein. It demonstrated structural and functional stability in the pH range 5.0-12.0 and up to70 °C temperature. Further decrease in pH and increase in temperature induces unfolding followed by aggregation. Chemical induced denaturation was found to be cooperative and transitions were reversible and sigmoid. Tm (midpoint of denaturation), ΔCp (constant pressure heat capacity change) and ΔHm (van't Hoff enthalpy change at Tm were calculated to be 41.25 ± 0.2 °C, 1.3 ± 0.07 kcal mol−1K−1 and 61 ± 2 kcal mol−1 respectively for thermally denatured ASPI earlier. The reversibility of the protein was confirmed for both thermally and chemically denatured ASPI. The results obtained from trypsin inhibitory activity assay and structural studies are found to be in a significant correlation and hence established structure-function relationship of ASPI.

Original languageEnglish (US)
Pages (from-to)415-423
Number of pages9
JournalInternational Journal of Biological Macromolecules
Volume103
DOIs
StatePublished - Oct 2017
Externally publishedYes

Keywords

  • Allium sativum Protease Inhibitor
  • Denaturation studies
  • Protein folding
  • Protein stability
  • Protein unfolding
  • Trypsin inhibitor

ASJC Scopus subject areas

  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Economics and Econometrics
  • Energy(all)

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