Ni Nyoman Tri Puspaningsih, Prof. Dr., Dra., M.Si
(2012)
Peningkatan aktivitas enzim hemiselulase dengan rekayasa protein untuk pengolahan biomassa berbasis lignoselulosa.
UNIVERSITAS AIRLANGGA.
(Unpublished)
Abstract
The purpose of this research is to investigate the substrate stereospecificity of IlL- arabinofuranosidase GH51 Geobacillus thermoleovorans IT-08 (AbfA) toward Mycobacteria cell wall. In general, there are 3 stages in this research are (1) the production of AbfA recombinant from E. coli BL21 (DE3)/pET-abfA, (2) specific activity assay of AbfA recombinant, (3) substrate stereospecificity analysis of AbfA in silico. In laboratory methods, AbfA has hydrolase activity toward Darabinofuranoside (H37Rv and BFCC). However its activity toward Larabinofuranoside (arabinogalactan, pectin, oat spelt xylan and arabinan) higher than its hydrolase activity toward D-arabinofuranoside (H37Rv and BFCC). On silico analysis, hydrolase activity AbfA toward D-arabinofuranoside may occur due to fingerprint interactions between the ligand and catalytic residue Glu294. Based on in silico analysis, the catalytic mechanism of AbfA toward D-arabinofuranoside was suggested following model catalytic mechanism of a-L-arabinofuranosidase GHSI toward L-arabinofuranoside substrate. Effect of sterie hindrance by Trp99 and Trp298 at the sub-site -1 rationalize the substrate specificity toward D-arabinofuranoside lower than L-arabinofuranoside. This thesis research was the first reported that AbfA has catalytic activity toward D-Arabinofuranoside derived from Mycobacteria cell wall.
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