| 摘要 |
PURPOSE:To obtain a new DNA sequence encoding for a modification type RNase T1 prepared by replacing tyrosine at a specific position of a natural type RNase Tq with tryptophan and providing a modification type RNase having improved activity by incorporation to a manifestation vector. CONSTITUTION:This new DNA sequence codes for a modification type RNase T1 prepared by replacing tyrosine at the 45th$ from the amino end of a natural type RNase T1 with tryptophan, has a base sequence of the formula and is capable of producing a new modification type RNase T1 having 42% higher activity than natural type RNase T1 by incorporating the sequence to a manifestation vector, transducing and transforming a host such as Escherichia coli, culturing the transformant and manifesting the gene. The DNA sequence is obtained by dividing the whole DNA sequence into several oligonucleotide units, synthesizing each part by phosphoric triester method and ligating each prepared oligonucleotide. |
