Characterization of a prokaryotic topoisomerase I activity in chloroplast extracts from spinach
Open Access
- 11 March 1983
- journal article
- research article
- Published by Oxford University Press (OUP) in Nucleic Acids Research
- Vol. 11 (5) , 1523-1536
- https://doi.org/10.1093/nar/11.5.1523
Abstract
A topoisomerase I activity has been partially purified from crude extracts of spinach chloroplasts. This activity relaxes the supercoiled covalently closed circular DNA of pBR322. The enzyme requires Mg++ , but not ATP, and has an apparent molecular weight of about 115,000. It catalyzes a unit change in the linkage number of supercoiled DNA but cannot relax positive supercoiled DNA. These characteristics of the topoisomerase suggest it is of the prokaryotic type and would tend to support the endosymbiotic theory of plastid origin and evolution.Keywords
This publication has 25 references indexed in Scilit:
- Eukaryotic DNA topoisomerases: two forms of type I DNA topoisomerases from HeLa cell nuclei.Proceedings of the National Academy of Sciences, 1981
- A γ‐like DNA Polymerase in Spinach ChloroplastsEuropean Journal of Biochemistry, 1980
- Analysis of Covalent Complexes Formed between Calf Thymus DNA Topisomerase and Single-Stranded DNAEuropean Journal of Biochemistry, 1980
- Mitochondria contain a distinct DNA topoisomerase.Journal of Biological Chemistry, 1979
- Nucleotide sequence of small ColE1 derivatives: Structure of the regions essential for autonomous replication and colicin E1 immunityMolecular Genetics and Genomics, 1979
- A DNA nicking-closing enzyme encapsidated in vaccinia virus: partial purification and properties.Proceedings of the National Academy of Sciences, 1977
- Evolution of Organelles and Eukaryotic GenomesScience, 1975
- Symbiotic theory of the origin of eukaryotic organelles; criteria for proof.1975
- An Activity from Mammalian Cells That Untwists Superhelical DNA—A Possible Swivel For DNA ReplicationProceedings of the National Academy of Sciences, 1972
- A Method for Determining the Sedimentation Behavior of Enzymes: Application to Protein MixturesJournal of Biological Chemistry, 1961