1SVO

Structure of SV40 large T antigen helicase domain

Summary for 1SVO

• Entry DOI: 10.2210/pdb1svo/pdb
• Descriptor: large T antigen, ZINC ION (3 entities in total)
• Functional Keywords: aaa+ fold, viral protein
• Biological source: Simian virus 40
• Cellular location: Host nucleus: P03070
• Total number of polymer chains: 2
• Total formula weight: 87213.66

Authors

Gai, D.,Zhao, R.,Finkielstein, C.V.,Chen, X.S. (deposition date: 2004-03-29, release date: 2004-10-19, Last modification date: 2024-11-06)

Primary citation

Gai, D.,Zhao, R.,Li, D.,Finkielstein, C.V.,Chen, X.S.
Mechanisms of conformational change for a replicative hexameric helicase of SV40 large tumor antigen.
Cell(Cambridge,Mass.), 119:47-60, 2004

PubMed Abstract: The large tumor antigen (LTag) of simian virus 40, an AAA(+) protein, is a hexameric helicase essential for viral DNA replication in eukaryotic cells. LTag functions as an efficient molecular machine powered by ATP binding and hydrolysis for origin DNA melting and replication fork unwinding. To understand how ATP binding and hydrolysis are coupled to conformational changes, we have determined high-resolution structures ( approximately 1.9 A) of LTag hexamers in distinct nucleotide binding states. The structural differences of LTag in various nucleotide states detail the molecular mechanisms of conformational changes triggered by ATP binding/hydrolysis and reveal a potential mechanism of concerted nucleotide binding and hydrolysis. During these conformational changes, the angles and orientations between domains of a monomer alter, creating an "iris"-like motion in the hexamer. Additionally, six unique beta hairpins on the channel surface move longitudinally along the central channel, possibly serving as a motor for pulling DNA into the LTag double hexamer for unwinding.

PubMed: 15454080
DOI: 10.1016/j.cell.2004.09.017

Experimental method

X-RAY DIFFRACTION (2.6 Å)