Assembly of a Chromosomal Replication Machine: Two DNA Polymerases, a Clamp Loader, and Sliding Clamps in One Holoenzyme Particle. I. ORGANIZATION OF THE CLAMP LOADER
| Autor: | Vytautas Naktinis, Jennifer Turner, Jeff Finkelstein, Rene Onrust, Mike O'Donnell, Linhua Fang |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
DNA Replication
DNA Bacterial Genetics DNA clamp biology DNA polymerase Protein subunit DNA replication RNA-dependent RNA polymerase Cell Biology Chromosomes Bacterial Biochemistry chemistry.chemical_compound DNA polymerase III holoenzyme chemistry dnaX Escherichia coli Biophysics biology.protein Electrophoresis Polyacrylamide Gel Molecular Biology Chromatography High Pressure Liquid DNA DNA Polymerase III |
| Zdroj: | Journal of Biological Chemistry. 270:13348-13357 |
| ISSN: | 0021-9258 3378-1338 |
| DOI: | 10.1074/jbc.270.22.13348 |
| Popis: | The gamma complex of DNA polymerase III holoenzyme, the replicase of Escherichia coli, couples ATP hydrolysis to the loading of beta sliding clamps onto primed DNA. The beta sliding clamp tethers the holoenzyme replicase to DNA for rapid and processive synthesis. In this report, the gamma complex has been constituted from its five different subunits. Size measurements and subunit stoichiometry studies show a composition of gamma 2 delta 1 delta' 1 1 chi 1 psi 1. Strong intersubunit contacts have been identified by gel filtration, and weaker contacts were identified by surface plasmon resonance measurements. An analogous tau complex has also been constituted and characterized; it is nearly as active as the gamma complex in clamp loading activity, but as shown in the fourth report of this series, it is at a disadvantage in binding the delta, delta', chi, and psi subunits when core is present (Xiao, H., Naktinis, V., and O'Donnell, M. (1995) J. Biol. Chem. 270, 13378-13383). The single copy subunits within the gamma complex provide the basis for the structural asymmetry inherent within DNA polymerase III holoenzyme. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|