Enhancement of the activity and pH-performance of chitosanase from Bacilluscereus strains by DNA shuffling |
| |
Authors: | Yu-Mi Park and Sa-Youl Ghim |
| |
Institution: | (1) Department of Microbiology, College of Natural Sciences, Kyungpook National University, #1370 Sankyug-Dong, Buk-Gu, Daegu, 702-701, Korea |
| |
Abstract: | DNA shuffling was carried out with two chitosanase genes belonging to glycoside hydrolase family eight from Bacillus cereus KNUC51 and B. cereus KNUC55. The shuffled products, YM18 and YM20, which showed higher activity than the parents at 40°C, were selected for further
studies. The 50 kDa chitosanases were purified using affinity chromatography with glutathione-Sepharose 4B. In general, the
specific activity of YM18 is enhanced 250% and that of YM20 is 350% compared to the parents. YM20 exhibits a shift of the
optimal pH level from 5.5 to 6.5. DNA sequence analysis revealed that YM18 and YM20 contained 2 amino acid substitutions (I13T
and A87V for YM18; K66R and N352S for YM20). We presumed that these amino acid substitutions increase the specific activity
and change the property of the two variants.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. |
| |
Keywords: | Bacillus cereus Chitooligosaccharide Chitosanase DNA shuffling Shift of optimal pH |
本文献已被 SpringerLink 等数据库收录! |
|