Mosquitocidal Proteins from Escheriachia coli pSL 2-1 Clone and Bacillus sphaericus 1593

Escheriachia coli pSL 2-1 클론과 Bacillus sphaericus 1593 균주가 생산한 모기치사 단백질

A clone pSL 2-1, which is a recombinant plasmid believed to contain the mosquitocidal crystal-line protein gene of the Bacillus sphaericus 1593, was expressed in Escherichia coli JM83 and the product of the clone was purified and identified. The unsolubilized mosquitocidal crystal proteins from the B. sphaericus had formed 43, 58, 64, 100, 113, and 130 Kd bands in the SDS-polyacrylamide gel, but the NaOH-solublized proteins at pH 12 formed 2 protein bands of 43- and 64Kd in the gel because the larger protein (precursor) bands were cleaved. The products of the pSL 2-1 clone was purified by Sephadex G-200 and only the fractions having lethal activity to the 3rd in-star larvae of mosquito Culex pipiens were analyzed by the gel. The only single protein band of 42 Kd toxic to the larvae was formed. The major toxic protein being produced from the B. sphaericus 1593 and the pSL 2-1 clone was found to be the 42 Kd.

Escheriachia coli pSL 2-1 clone은 Bacillus sphaericus 1593의 모기살충 유전자를 클로닝한 재조합 DNA이다. 이 클론이 생산하는 살충독소 단백질의 분자량을 SDS-polyacrylamide gel을 이용하여 측정했다. B. sphaericus 1593균이 생산하는 독소결정체를 분리하여 전기영동을 한 결과는 6개의 단백질밴드(43, 58, 64, 100, 113, 130Kd)가 형성되었으나, 독소결정체를 알칼리 pH로 용해하여 전기영동을 하면 2개의 단백질 밴드(43과 64Kd)만이 나타났다. 그러나 대장균 pSL2-1균이 생산하는 독소단백질을 Sephadex G-200으로 정제하여 모기유충에 살충력이 있는 단백질을 전기영동한 결과는 42Kd만이 나타났다. LC50은 2 $\mu\textrm{g}$/$m\ell$이었다. B. sphaericus와 pSL2-1 clone 생산하는 살충단백질은 42Kd 단백질인 것으로 생각된다.