A gene ·( eg1 ) .I..g for an endoglucanase I ( EGI ) was cloned from Trichoderma pseudokoningii strain 3. 3002. The gene was composed of 1 566 bp, interrupted by 2 introns, and coding for 461 amino acid residues. The deduced amino acid sequence of EGI revealed a multi-domain structure composed of a 22 aa signal peptide, a catalytic domain, a linker, and a cellulose-binding domain from the N-terminus. The eg gene with no introns was obtained by overlap PCR, and the sequence encoding the mature peptide was inserted into the Saccharomyces cerevisiae secretion vector pYEa. The recombiaat expression plasmid pYEα-Pegl was constructed and then transformed into 5. Cerevisiae, along with the yeasts transformed with vector pYEa as controls. After induction of galactose, the resulting S. Cerevisiae transformant secreted a recombinant EGI that had enzymatic properties detected by congo red assay and enzyme activity assay. The expression was confirmed by a protein band in the SDS-PAGE, which is a little larger than predicted EGI.%从拟康氏木霉3.3002基因组中克隆了内切葡聚糖酶EGI基因,该基因全长1566 bp,由3个外显子2个内含子组成,编码461个氨基酸.编码蛋白EGI的N端为22aa组成的信号肽,其后依次为催化结构域、连接肽和结合结构域.采用重叠PCR法获得无内含子的内切葡聚糖酶基因eg1,并将其成熟肽编码序列插入酿酒酵母分泌型表达载体pYEα中,构建成pYEα-Peg1重组质粒,转化酿酒酵母.重组转化子经β-半乳糖诱导,检测表达产物的分子大小以及酶活,结果表明,转化子在刚果红平板上可产生明显的水解圈；酶活检测显示该基因能在酿酒酵母中表达有生物活性的EG I并分泌到胞外；SDS-PAGE电泳显示EGI蛋白分子量比预期目的蛋白稍偏大.
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