The Simian virus 40 T antigen double hexamer assembles around the DNA at the replication origin Journal Article
| Authors: | Dean, F. B.; Borowiec, J. A.; Eki, T.; Hurwitz, J. |
| Article Title: | The Simian virus 40 T antigen double hexamer assembles around the DNA at the replication origin |
| Abstract: | An initial step in the replication of simian virus (SV40) DNA is the ATP-dependent formation of a double hexamer of the SV40 large tumor (T) antigen at the SV40 DNA replication origin. In the absence of DNA, T antigen assembled into hexamers in the presence of magnesium and ATP. Hexameric T antigen was stable and could be isolated by glycerol gradient centrifugation. The ATPase activities of hexameric and monomeric T antigen isolated from parallel glycerol gradients were identical. However, while monomeric T antigen was active in the ATP-dependent binding, untwisting, unwinding, and replication of SV40 origin-containing DNA, hexameric T antigen was inactive in these reactions. Isolated hexamers incubated at 37°C in the presence of ATP remained intact, but dissociated into monomers when incubated at 37°C in the absence of ATP. This dissociation restored the activity of these preparations in the DNA replication reaction, indicating that hexameric T antigen is not permanently inactivated but merely assembled into a nonproductive structure. We propose that the two hexamers of T antigen at the SV40 origin assemble around the DNA from monomer T antigen in solution. This complex untwists the DNA at the origin, melting specific DNA sequences. The resulting single-stranded regions may be utilized by the T antigen helicase activity to initiate DNA unwinding bidirectionally from the origin. |
| Keywords: | nonhuman; dna replication; animal; electron microscopy; microscopy, electron; protein assembly; protein binding; enzyme activity; transfection; kinetics; recombinant proteins; virus large t antigen; simian virus 40; dna, viral; models, genetic; helicase; adenosine triphosphate; dna replication origin; antigen binding; antigens, polyomavirus transforming; adenosine triphosphatase; centrifugation; hydrolysis; dissociation; monomer; protein dna interaction; dna denaturation; magnesium; gel electrophoresis; virus dna; insects; baculoviridae; simiae; antigen purification; simian virus; priority journal; article; support, u.s. gov't, p.h.s.; macromolecular systems |
| Journal Title: | Journal of Biological Chemistry |
| Volume: | 267 |
| Issue: | 20 |
| ISSN: | 0021-9258 |
| Publisher: | American Society for Biochemistry and Molecular Biology |
| Date Published: | 1992-07-15 |
| Start Page: | 14129 |
| End Page: | 14137 |
| Language: | English |
| PUBMED: | 1321135 |
| PROVIDER: | scopus |
| DOI: | 10.1016/S0021-9258(19)49688-9 |
| DOI/URL: | |
| Notes: | Article -- Source: Scopus |
Altmetric
Citation Impact
BMJ Impact Analytics
Related MSK Work