Mode of action and antifungal properties of two cold-adapted chitinases.
The mode of action of two chitinases from the Antarctic Arthrobacter sp. strain TAD20 on N-acetyl-chitooligomers and chitin polymers has been elucidated. Identification of the length of chitin oligomers following enzymatic hydrolysis was verified by using HPLC-based analysis. It was observed that the length of the oligomer is important for enzyme action. The enzymes cannot effectively hydrolyze chitin oligomers with a degree of polymerization lower than four. ArChiA is an endochitinase which hydrolyzes chitin substrates randomly, whereas ArChiB is an exochitinase which degrades chitin chains and N-acetyl-chitooligomers from the nonreducing end, releasing N- N'-diacetyl-chitobiose. ArChiB (100 microg/ml) inhibited spore germination and hyphal elongation of the phytopathogenic fungus Botrytis cinerea by 15% and 30%, respectively. A more pronounced effect was observed with ArChiA (100 microg/ml) resulting in 70% inhibition of spore germination and 60% inhibition of germ tube elongation. A slight additive effect was observed, when the two enzymes were used in combination, only on the inhibition of germ tube elongation.
Mavromatis
Konstantinos
K
Department of Biology, Division of Applied Biology and Biotechnology, University of Crete, PO Box 1470, 71110 Heraklion, Crete, Greece.
Lorito
Matteo
M
Woo
Sheridan L
SL
Bouriotis
Vassilis
V
D000935:Antifungal Agents / Q000378:metabolism / Q000494:pharmacology*; D020171:Botrytis / Q000187:drug effects* / Q000502:physiology; D002686:Chitin / Q000378:metabolism; D002688:Chitinases / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D003080:Cold Temperature; D009844:Oligosaccharides / Q000378:metabolism
D000935:Antifungal Agents; D009844:Oligosaccharides; D002686:Chitin; D002688:Chitinases