ESCHERICHIA COLI RIBONUCLEASE H HAVING ARTIFICIAL DISULFIDE BOND

摘要

PURPOSE:To provide the subject Escherichia coli polynucleotide He having an amino acid sequence in which asparagine and cysteine at the specific number positions in the amino acid sequence are substituted with cysteine and alanine, respectively, capable of being replicated in Escherichia coli cell and giving a manifestation vector containing a replication source originated from plasmid pUC 18. CONSTITUTION:A reduction type variant ribonuclease H having an amino acid sequence in which asparagine at the 44th position is substituted with cysteine and cysteine at the 63th and 133th positions also with alanine. A transformant transformed with the abovementioned manifestation vector and enabling to produce the variant ribonuclease H is obtained. The culture of the transformant allows to prepare the reduction type variant ribonuclease H. The reduction type variant ribonuclease H is oxidized e.g. with glutathione redox buffer to provide an oxidation type variant ribonuclease H having a S-S bond therein.