Purification and characterization of normal and mutant forms of T4 endonuclease V.

Y. Nakabeppu, K. Yamashita, M. Sekiguchi

研究成果: Contribution to journalArticle査読

96 被引用数 (Scopus)


Endonuclease V of bacteriophage T4 has been purified to physical homogeneity from T4D-infected Escherichia coli 1100. The enzyme, whose molecular weight is 16,000, possessed two distinct catalytic activities, a pyrimidine dimer-DNA glycosylase and an apurinic/apyrimidinic endonuclease. They acted on UV-irradiated poly(dA) . poly(dT) in a sequential manner; the glycosylase cleaved the N-glycosyl bond between the 5'-pyrimidine of a dimer and the corresponding sugar and then the endonuclease hydrolyzed a phosphodiester bond on the 3'-side of the apyrimidinic site. The 5'-termini thus generated were phosphorylated by T4 polynucleotide kinase only after they had been subjected to direct photoreversal and then treated with alkaline phosphatase. By using two phage mutants, uvs-5 and uvs-13, it was shown that occurrence of an amber mutation in the denV gene caused a simultaneous loss of the two activities. Suppression of the mutation of uvs-5 rendered both activities partially active. When the mutation of uvs-13 was suppressed, a mutant form of enzyme that possessed only a glycosylase activity was produced. This suggests that there are two distinct domains in a single enzyme, each of which corresponds to one of the activities.

ジャーナルJournal of Biological Chemistry
出版ステータス出版済み - 3 10 1982

All Science Journal Classification (ASJC) codes

  • 生化学
  • 分子生物学
  • 細胞生物学


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