中国生物工程杂志

Chromhalobacter sp.NJS-2 was isolated from Antarctica deep-sea sediment. The ectABC gene from this strain was amplified by PCR，consisting of 2,378bp. Analysis of the OMIGA software showed that the whole sequence involves three open reading fragments, which were 576bp、1272bp and 393bp. They encoded L-diaminobutyric acid transaminase (EctB)，L-diaminobutyric acid acetyl transferase (EctA), and ectoine synthase (EctC), respectively. The amplified fragment of ectA was cloned into the expression vector pET-his. The insert position, the size and the reading frame were identified by PCR, restriction digestion and the sequence analysis of the recombinant plasmids. SDS-PAGE showed that the relative molecular mass of the expression product was 21 KD as predicted, which indicated that the recombinant plasmids could express the gene of L-diaminobutyric acid acetyl transferase. Enzyme activity detection of purified EctA partially elucidated the biosynthetic pathway of ectoine.