Synthesis and Secretion of the Endo-$\beta$-l,4-Glucanase from Bacillus subtilis in Industrial Yeast Strain

산업용 효모에서 Bacillus subtilis Endo-$\beta$-1,4-Glucanase의 생합성 및 분비

DNA segment encoding $\beta$-1, 4-glucanase of Bacillus subtilis was fused in frame to mouse $\alpha$-amylase signal sequence behind the alcohol dehydrogenase isoenzyme I gene (ADHI) promoter of the yeast expression vector pMS12. To enhance the expression level of the $\beta$glucanase gene in yeast, transcription terminator sequence iso-1-cytochrome c gene (CYCI) was inserted into the recombinant plasmid. The transformants harbouring such recombinant plasmids secreted $\beta$-glucanase into the culture medium. The expresstion level of the $\beta$-glucanase gene was increased about 2-fold caused by inserting the terminator. The amount of the secreted $\beta$-glucanase in culture medium was approximately 60% of the total quantity synthesized.

Bacillus subtilis의 Beta-1,4-glucanase 유전자와 Saccharomyces cerevisiae의 alcohol dehydrogenase isoenzyme I 유전자 (ADHI)의 promoter와 mouse $\alpha$-amylase의 분비신호를 연결하여 분비형 플라스미드를 구성하였으며 이를 산업용 알콜생산 효모인 Saccharomyces cerevisiae 54에 도입하여 형질전환시켰다. 한편 $\beta$-glucanase 유전자의 발현정도를 증대시키기 위해 CYC1 유전자의 전사종결신호를 부가한 후 역시 Saccharomyces cerevisiae 54에 도입하였다. 형질전체들은 carboxymethyl cellulose가 함유된 평판배지에서 $\beta$-glucanase를 분비하고 있음을 확인할 수 있었다. 전사종결 신호가 부가된 경우엔 전체역가가 2배 정도 증가하였다. 형질전환체들이 세포밖으로 분비한 효소역가는 전체의 60 정도였다.