Effect of copper oxide nanoparticles on the conformation and activity of β-galactosidase

Gulam Rabbani, Mohd Jahir Khan, Abrar Ahmad, Mohamad Yusof Maskat, Rizwan Hasan Khan

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

The primary objective of this study is to explore the interaction of β-galactosidase with copper oxide nanoparticles (CuO NPs). Steady-state absorption, fluorescence and circular dichroism (CD) spectroscopic techniques have been employed to unveil the conformational changes of β-galactosidase induced by the binding of CuO NPs. Temperature dependent fluorescence quenching results indicates a static quenching mechanism in the present case. The binding thermodynamic parameters delineate the predominant role of H-bonding and van der Waals forces between β-galactosidase and CuO NPs binding process. The binding was studied by isothermal titration calorimetry (ITC) and the result revealed that the complexation is enthalpy driven, the δH°<0, δS°<0 indicates the formation of hydrogen bonds between β-galactosidase and CuO NPs occurs. Disruption of the native conformation of the protein upon binding with CuO NPs is reflected through a reduced functionality (in terms of hydrolase activity) of the protein CuO NPs conjugate system in comparison to the native protein and CuO NPs exhibited a competitive mode of inhibition. This also supports the general belief that H-bond formation occurs with NPs is associated with a lesser extent of modification in the native structure. Morphological features and size distributions were investigated using transmission electron microscopy (TEM) and dynamic light scattering (DLS). Additionally the considerable increase in the Rh following the addition of CuO NPs accounts for the unfolding of β-galactosidase. Chemical and thermal unfolding of β-galactosidase, when carried out in the presence of CuO NPs, also indicated a small perturbation in the protein structure. These alterations in functional activity of nanoparticle bound β-galactosidase which will have important consequences should be taken into consideration while using nanoparticles for diagnostic and therapeutic purposes.

Original languageEnglish
Pages (from-to)96-105
Number of pages10
JournalColloids and Surfaces B: Biointerfaces
Volume123
DOIs
Publication statusPublished - 1 Nov 2014

Fingerprint

Galactosidases
Copper oxides
copper oxides
Nanoparticles
Oxides
Conformations
Copper
nanoparticles
proteins
quenching
Proteins
fluorescence
Quenching
Van der Waals forces
Fluorescence
titration
Hydrolases
dichroism
Calorimetry
light scattering

Keywords

  • Circular dichroism
  • Copper oxide nanoparticles
  • Dynamic light scattering
  • Guanidinium hydrochloride unfolding
  • Hydrolase activity
  • Thermal denaturation
  • β-Galactosidase

ASJC Scopus subject areas

  • Biotechnology
  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry
  • Surfaces and Interfaces

Cite this

Effect of copper oxide nanoparticles on the conformation and activity of β-galactosidase. / Rabbani, Gulam; Khan, Mohd Jahir; Ahmad, Abrar; Maskat, Mohamad Yusof; Khan, Rizwan Hasan.

In: Colloids and Surfaces B: Biointerfaces, Vol. 123, 01.11.2014, p. 96-105.

Research output: Contribution to journalArticle

Rabbani, Gulam ; Khan, Mohd Jahir ; Ahmad, Abrar ; Maskat, Mohamad Yusof ; Khan, Rizwan Hasan. / Effect of copper oxide nanoparticles on the conformation and activity of β-galactosidase. In: Colloids and Surfaces B: Biointerfaces. 2014 ; Vol. 123. pp. 96-105.
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