Chernin L S, De la Fuente L, Sobolev V, Haran S, Vorgias C E, Oppenheim A B, Chet I
Otto Warburg Center for Biotechnology in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Israel.
Appl Environ Microbiol. 1997 Mar;63(3):834-9. doi: 10.1128/aem.63.3.834-839.1997.
The gene chiA, which codes for endochitinase, was cloned from a soilborne Enterobacter agglomerans. Its complete sequence was determined, and the deduced amino acid sequence of the enzyme designated Chia_Entag yielded an open reading frame coding for 562 amino acids of a 61-kDa precursor protein with a putative leader peptide at its N terminus. The nucleotide and polypeptide sequences of Chia_Entag showed 86.8 and 87.7% identity with the corresponding gene and enzyme, Chia_Serma, of Serratia marcescens, respectively. Homology modeling of Chia_Entag's three-dimensional structure demonstrated that most amino acid substitutions are at solvent-accessible sites. Escherichia coli JM109 carrying the E. agglomerans chiA gene produced and secreted Chia_Entag. The antifungal activity of the secreted endochitinase was demonstrated in vitro by inhibition of Fusarium oxysporum spore germination. The transformed strain inhibited Rhizoctonia solani growth on plates and the root rot disease caused by this fungus in cotton seedlings under greenhouse conditions.
编码内切几丁质酶的chiA基因是从土壤中的成团肠杆菌中克隆出来的。测定了其完整序列，该酶推导的氨基酸序列Chia_Entag产生了一个开放阅读框，编码一个61 kDa前体蛋白的562个氨基酸，其N端有一个推定的前导肽。Chia_Entag的核苷酸和多肽序列与粘质沙雷氏菌相应的基因和酶Chia_Serma分别具有86.8%和87.7%的同一性。Chia_Entag三维结构的同源性建模表明，大多数氨基酸取代位于溶剂可及的位点。携带成团肠杆菌chiA基因的大肠杆菌JM109产生并分泌了Chia_Entag。通过抑制尖孢镰刀菌孢子萌发在体外证明了分泌的内切几丁质酶的抗真菌活性。在温室条件下，转化菌株抑制了平板上立枯丝核菌的生长以及该真菌在棉花幼苗中引起的根腐病。
