Biological Assembly 1  

 3D View: Structure | Ligand Interaction

Global Symmetry: Cyclic - C6  (3D View)
Global Stoichiometry: Homo 6-mer - A6 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 87.21 kDa 
• Atom Count: 6056 
• Modelled Residue Count: 724 
• Deposited Residue Count: 754 
• Unique protein chains: 1

1SVO

Structure of SV40 large T antigen helicase domain

• DOI: 10.2210/pdb1SVO/pdb

• Classification: VIRAL PROTEIN
• Organism(s): Macaca mulatta polyomavirus 1
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2004-03-29 Released: 2004-10-19 
• Deposition Author(s): Gai, D., Zhao, R., Finkielstein, C.V., Chen, X.S.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.60 Å
• R-Value Free: 0.271 
• R-Value Work: 0.233 

Literature

Mechanisms of conformational change for a replicative hexameric helicase of SV40 large tumor antigen.

Gai, D., Zhao, R., Li, D., Finkielstein, C.V., Chen, X.S.

(2004) Cell 119: 47-60

• PubMed: 15454080 
• DOI: 10.1016/j.cell.2004.09.017
• Primary Citation of Related Structures:  
  1SVO, 1SVM, 1SVL


• 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.

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Organizational Affiliation: 

Department of Biochemistry and Molecular Genetics, University of Colorado Health Sciences Center, Denver, CO 80262, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
large T antigen	A, B	377	Macaca mulatta polyomavirus 1	Mutation(s): 0  EC: 3.6.4
Find proteins for P03070 (Simian virus 40) Explore P03070  Go to UniProtKB:  P03070

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
ZN	A, B	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.60 Å
• R-Value Free: 0.271 
• R-Value Work: 0.233 
• Space Group: P 3 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 120.444	α = 90
b = 120.444	β = 90
c = 131.767	γ = 120

Software Package:

Software Name	Purpose
HKL-2000	data collection
SCALEPACK	data scaling
CNS	refinement
HKL-2000	data reduction
CNS	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2004-03-29 
• Released Date: 2004-10-19 
Deposition Author(s): Gai, D., Zhao, R., Finkielstein, C.V., Chen, X.S.

Revision History  

• Version 1.0: 2004-10-19
  Type: Initial release
  
• Version 1.1: 2008-04-30
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance