Effect of substrate-binding domain on the antifungal activity of chitinase
Date Issued
2006
Date
2006
Author(s)
Guo, Shu-Huei
DOI
zh-TW
Abstract
Bacillus circulans WL-12 and Bacillus cereus 28-9 are chitinase-producing bacteria. B. circulans WL-12 excretes at least six different chitinases, and ChiA1 is the main chitinolytic enzyme. In our previous study, ChiA1 showed very weak or no inhibitory activity on conidial germination of Botrytis elliptica. B. cereus 28-9 produces two chitinase, ChiCW and ChiCH. An in vitro assay showed that ChiCW had inhibitory activity on conidial germination of B. elliptica. ChiA1 and ChiCW have three kinds of domains, catalytic domain, fibronectin type III-like domain and substrate-binding domain. The substrate-binding domains of chitinases have been identified to play an important role in binding activities. In this study, the effect of the substrate-binding domain with the activity of ChiA1 and ChiCW toward fungi were examined. Deletion and replacement of the chitin-binding domain of ChiA1 generated three deletion mutants and three recombinants in that the chitin-binding domain of ChiA1 was replaced by the chitin-binding domain of ChiCW. Chitin-binding domain (and FN3 domain) deleted ChiA1 showed low hydrolytic activity toward colloidal chitin substrate; however, the hydrolytic activity regained by a fusion with the chitin-binding domain of ChiCW. In order to understand the effect of chitin-binding domain, ChiA1(C-2F)W(B) and ChiA1(C-2F) were purified from E. coli harboring pNTU129 and pNTU124. ChiA1(C-2F) also had very weak inhibitory activity like ChiA1, but ChiA1(C-2F)W(B) had 40% inhibitory activity on conidial germination of B. elliptica. It revealed that the chitin-binding domain of ChiCW could provide the antifungal capability to a chitinase originally lack of antifungal activity, especially toward B. elliptica.
Subjects
Bacillus circulans
Bacillus cereus
ChiA1
ChiCW
幾丁質分解酵素
chitinase
chitin-binding domain
Type
other
File(s)![Thumbnail Image]()
Loading...
Name
ntu-95-R93633021-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):50e38aa3ac5b027e461d816aa792750b