Mapping the active-site tyrosine of vaccinia virus DNA topoisomerase I Journal Article
| Authors: | Shuman, S.; Kane, E. M.; Morham, S. G. |
| Article Title: | Mapping the active-site tyrosine of vaccinia virus DNA topoisomerase I |
| Abstract: | Site-directed mutagenesis of the vaccinia virus gene encoding a type I DNA topoisomerase implicates Tyr-274 as the active-site residue that forms a covalent adduct with DNA during cycles of DNA-strand breakage and reunion. Replacement of Tyr-274 by phenylalanine results in loss of the ability of the enzyme to relax negatively supercoiled DNA as well as to form the covalent DNA-protein intermediate. Substitution of phenylalanine for tyrosine at nine other sites in the protein has no apparent effect on enzyme activity. Amino acid sequence alignment reveals Tyr-274 to be homologous to Tyr-727 and Tyr-771, respectively, of the type I topoisomerases from Saccharomyces cerevisiae and Saccharomyces pombe; Tyr-727 and Tyr-771 have been shown to represent the active-site tyrosines of those enzymes. Sequence comparison of the active-site regions defines a motif Ser-Lys-Xaa-Xaa-Tyr common to the viral and cellular type I topoisomerases, including the human enzyme. |
| Keywords: | mutation; nonhuman; comparative study; gene expression; structure activity relation; tyrosine; cloning, molecular; molecular sequence data; saccharomyces cerevisiae; escherichia coli; recombinant proteins; vaccinia virus; base sequence; binding sites; codon; site directed mutagenesis; phenylalanine; dna topoisomerase; dna topoisomerases, type i; enzyme active site; covalent catalysis; vaccinia; virus dna; saccharomyces; saccharomyces pombe; priority journal; article; support, u.s. gov't, p.h.s.; genes, structural, viral; tyrosyl phosphodiester linkage; yeast topoisomerase |
| Journal Title: | Proceedings of the National Academy of Sciences of the United States of America |
| Volume: | 86 |
| Issue: | 24 |
| ISSN: | 0027-8424 |
| Publisher: | National Academy of Sciences |
| Date Published: | 1989-12-01 |
| Start Page: | 9793 |
| End Page: | 9797 |
| Language: | English |
| DOI: | 10.1073/pnas.86.24.9793 |
| PUBMED: | 2557629 |
| PROVIDER: | scopus |
| PMCID: | PMC298588 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 14 April 2020 -- Source: Scopus |
