Thermodynamics of ligand (substrate end product) binding to endoxylanase from Chainia sp. (NCL-82-5-1): isothermal calorimetry and fluorescence titration studies

Hegde, Subray S and Kumar, Ameeta R and Ganesh, Krishna N and Swaminathan, Chittoor P and Khan, M Islam (1998) Thermodynamics of ligand (substrate end product) binding to endoxylanase from Chainia sp. (NCL-82-5-1): isothermal calorimetry and fluorescence titration studies. In: Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1388 (01). pp. 93-100.

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Abstract

The binding of xylo-oligosaccharides to Chainia endoxylanase resulted in a decrease in fluorescence intensity of the enzyme with the formation of 1:1 complex. Equilibrium and thermodynamic parameters of ligand binding were determined by fluorescence titrations and titration calorimetry. The affinity of xylanase for the oligosaccharides increases in the order X-2 < X-3 < X-4 less than or equal to X-5. Contributions from the enthalpy towards the free energy change decreased with increasing chain length from X-2 to X-4, whereas an increase in entropy was observed, the change in enthalpy and entropy of binding being compensatory. The entropically driven binding process suggested that hydrophobic interactions as well as hydrogen bonds play a predominant role in ligand binding.

Item Type:	Journal Article
Publication:	Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Endoxylanase;Fluorescence quenching;Isothermal calorimetry; Substrate binding;Chainia sp.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	31 Dec 2009 06:21
Last Modified:	19 Sep 2010 05:28
URI:	http://eprints.iisc.ac.in/id/eprint/19418

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