Biochemical characterization of heterologously expressed chitinase 1 (Chi1) from an inky cap, Coprinellus congregatus

초록

Fungal cell walls consist of various glucans and chitin. Fungi produce chitinases for their growth and development. The inky cap, Coprinellus congregatus, produces at least two different chitinases during its life cycle. Chitinase 1 (chi1) is expresses throughout its life cycle while chitinase 2 (chi2) is expressed at the mushroom autolysing phase. The cloned cDNA of chi1 is successfully expressed as a fusion protein with c-myc in Pichia pastoris, and purified by the affinity chromatography. The optimum pH and temperature of Chi1 was pH 8.0 and 35°C, respectively when 4-nitrophenyl N,N',N''-triacetyl-β-D-chitotrioside was used as the substrate. The K<inf>m</inf> value and V<inf>max</inf> for the substrate was 0.780 mM and 0.10 OD min-1unit-1, respectively. The addition of purified Chi1 resulted in total growth inhibition against several plant pathogenic fungi such as Alternaria alternata, Fusarium graminearum and Trichoderma harzianum at the concentration of 60 μg/ml. © 2013, The Microbiological Society of Korea.

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