본 연구에서는 Serratia marcescens ATCC 27117 균주로부터 키나아제 유전자를 대장균으로 클로닝 하고 발현시켰다. pUC 19 플라스미드를 이용하여 S.marcescens의 genomic library를 만들고 팽화된 키틴이 포함된 한천배지에서 키티나아제 활성을 가지는 클론을 선별하였다. 약 1x10 transformant들 중에서 키티나아제 활성을 보이는 하나의 클론을 선발하였으며 이것은 pUC 19 플라스미드속에 8.9Kb 염색체 DNA 삽입단편을 가지고 있었다.
A chitinase gene of Serratia marcescens ATCC 27117 was cloned and expressed in Escherichiu di. A genomic library of S, marcescens was constructed with pUC 19 and screened using the swollen chitin agar plate for chitinolytic clones. A positive clone showing chitinclearance contains a recombinant pCHI 89, composed of 8.9 Kb chromosomal DNA fragment and pUC 19. Plasmid pCHI 89 produced 58 KD chitinase in E. coli, which was coincided with one of five extracellular chitinases produced by S. nzarccscens. Restriction endonuclease cleavage sites of the 8.9 Kb insert DNA fragment were mapped. E. coli JM109 harboring pCHI 89 inhibits the growth of a plant pathogenic fungus, Fusarium oxysporum.
