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Deletion of loop fragment adjacent to active site diminishes the stability and activity of exo-inulinase.
- Source :
-
International Journal of Biological Macromolecules . Nov2016, Vol. 92, p1234-1241. 8p. - Publication Year :
- 2016
-
Abstract
- Inulinases are classified as hydrolases and widely used in the food and medical industries. Here, we report the deletion of a six-membered adjacent active site loop fragment ( 74 YGSDVT 79 sequence) from third Ω-loop of the exo-inulinase containing aspartate residue from Aspergillus niger to study its structural and functional importance. Site-directed mutagenesis was used to create the mutant of the exo-inulinase (Δ6SL). To investigate the stability of the region spanning this loop, MD simulations were performed 80 ns for 20-85 residues. Molecular docking was performed to compare the interactions in the active sites of enzymes with fructose as a ligand. Accordingly, the functional thermostability of the exo-inulinase was significantly decreased upon loop fragment deletion. Evaluation of the kinetics parameters ( V max , K m , k cat and, k cat / K m ) and activation energy ( E a ) of the catalysis of enzymes indicated the importance of the deleted sequence on the catalytic performance of the enzyme. In conclusion, six-membered adjacent active site loop fragment not only plays a crucial role in the stability of the enzyme, but also it involves in the enzyme catalysis through lowering the activation energy of the catalysis and effective improving the catalytic performance. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 01418130
- Volume :
- 92
- Database :
- Academic Search Index
- Journal :
- International Journal of Biological Macromolecules
- Publication Type :
- Academic Journal
- Accession number :
- 118497091
- Full Text :
- https://doi.org/10.1016/j.ijbiomac.2016.08.039