1svm

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spinqualitylabelsall models 1svm, resolution 1.94Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Co-crystal structure of SV40 large T antigen helicase domain and ATP

Overview

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.

About this Structure

1SVM is a Single protein structure of sequence from Simian virus 40 with ZN, MG and ATP as ligands. The following page contains interesting information on the relation of 1SVM with [AAA+ Proteases]. Full crystallographic information is available from OCA.

Reference

Mechanisms of conformational change for a replicative hexameric helicase of SV40 large tumor antigen., Gai D, Zhao R, Li D, Finkielstein CV, Chen XS, Cell. 2004 Oct 1;119(1):47-60. PMID:15454080

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