Functional characterization, homology modeling and docking studies of beta-glucosidase responsible for bioactivation of cyanogenic hydroxynitrile glucosides from Leucaena leucocephala (subabul)

Shaik, Noor M and Misra, Anurag and Singh, Somesh and Fatangare, Amol B and Ramakumar, Suryanarayanarao and Rawal, Shuban K and Khan, Bashir M (2013) Functional characterization, homology modeling and docking studies of beta-glucosidase responsible for bioactivation of cyanogenic hydroxynitrile glucosides from Leucaena leucocephala (subabul). In: MOLECULAR BIOLOGY REPORTS, 40 (2). pp. 1351-1363.

PDF mol_bio_rep_40-2_1351_2013.pdf - Published Version Restricted to Registered users only Download (936kB) | Request a copy

Abstract

Glycosyl hydrolase family 1 beta-glucosidases are important enzymes that serve many diverse functions in plants including defense, whereby hydrolyzing the defensive compounds such as hydroxynitrile glucosides. A hydroxynitrile glucoside cleaving beta-glucosidase gene (Llbglu1) was isolated from Leucaena leucocephala, cloned into pET-28a (+) and expressed in E. coli BL21 (DE3) cells. The recombinant enzyme was purified by Ni-NTA affinity chromatography. The optimal temperature and pH for this beta-glucosidase were found to be 45 A degrees C and 4.8, respectively. The purified Llbglu1 enzyme hydrolyzed the synthetic glycosides, pNPGlucoside (pNPGlc) and pNPGalactoside (pNPGal). Also, the enzyme hydrolyzed amygdalin, a hydroxynitrile glycoside and a few of the tested flavonoid and isoflavonoid glucosides. The kinetic parameters K (m) and V (max) were found to be 38.59 mu M and 0.8237 mu M/mg/min for pNPGlc, whereas for pNPGal the values were observed as 1845 mu M and 0.1037 mu M/mg/min. In the present study, a three dimensional (3D) model of the Llbglu1 was built by MODELLER software to find out the substrate binding sites and the quality of the model was examined using the program PROCHEK. Docking studies indicated that conserved active site residues are Glu 199, Glu 413, His 153, Asn 198, Val 270, Asn 340, and Trp 462. Docking of rhodiocyanoside A with the modeled Llbglu1 resulted in a binding with free energy change (Delta G) of -5.52 kcal/mol on which basis rhodiocyanoside A could be considered as a potential substrate.

Item Type:	Journal Article
Publication:	MOLECULAR BIOLOGY REPORTS
Publisher:	SPRINGER
Additional Information:	Copyright for this article belongs to SPRINGER, NETHERLANDS
Keywords:	Glycosyl hydrolase family 1;Molecular docking;Homology modeling;Leucaena leucocephala
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	18 Feb 2013 08:52
Last Modified:	18 Feb 2013 08:52
URI:	http://eprints.iisc.ac.in/id/eprint/45763

Actions (login required)

View Item