[Two-codon mutagenesis of alpha-amylase gene of Bacillus amyloliquefaciens]

The oligonucleotide encoding Bam HI recognition site having the structure pCGGGATC had been inserted into the recognition sites MspI of the B. amyloliquefaciens alpha-amylase gene, which was cloned in pTG29B plasmid. The alpha-amylase gene had no BamHI sites before mutagenesis. The set of pNSBamHI plasmids with BamHI site at four different positions was obtained. It was shown that all the mutant alpha-amylases possess different specific activities. One of the mutant proteins possesses reduced thermostability. The mutant alpha-amylases can be used for further experiments on protein-engineering of liquefying-type alpha-amylases.