User:Udayan Shevade/Sandbox1
From Proteopedia
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=== Introduction === | === Introduction === | ||
| - | The SV40 large | + | The SV40 large tumor antigen is a multifunctional regulatory protein encoded by Simian Virus 40. It belongs to the AAA+ family of helicases <ref name="A">PMID:8946857</ref>. Noteworthy for its versatility, the protein is responsible for initiation of viral DNA replication, regulation of viral transcription and alteration of the host cell cycle to promote viral infectivity. Large T-antigen is an early gene product of SV40 and is translated after differential mRNA splicing. |
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==== The Origin Binding Domain ==== | ==== The Origin Binding Domain ==== | ||
| - | The obd monomer consists of | + | The obd monomer consists of five anti-parallel beta sheets flanked on either side by a pair of alpha helices. These monomers arrange tightly into a [http://www.pdb.org/pdb/explore/jmol.do?structureId=2FUF&bionumber=1 hexameric left-handed spiral], with 6 obd's per turn. Side-side interaction is necessary in hexamerization, for which residues <scene name='User:Udayan_Shevade/Sandbox1/Obd_183_185/1'>Phe 183 and Ser 185</scene> are crucial. The hexameric conformation creates a central channel 40 Angstroms wide, large enough for double stranded DNA, and positively charged. The pitch of the spiral complements that of DNA, allowing the specific assembly of a double hexamer at the origin of replication. Along the inner surface of the channel, <scene name='User:Udayan_Shevade/Sandbox1/Obd_residues/1'>the residues</scene> implicated in DNA binding are <scene name='User:Udayan_Shevade/Sandbox1/Obd_153_154_155/5'>Asn 153, Arg 154, Thr 155 from the A motif</scene>; <scene name='User:Udayan_Shevade/Sandbox1/Obd_203_204/1'>His 203, Arg 204 from the B2 motif</scene>; as well as <scene name='User:Udayan_Shevade/Sandbox1/Obd_201_202/1'>His 201 and Arg 202</scene><ref name="A"/>.</Structuresection> |
{{STRUCTURE_1svm| PDB=1svm | SCENE= }} | {{STRUCTURE_1svm| PDB=1svm | SCENE= }} | ||
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==== Helicase ==== | ==== Helicase ==== | ||
| - | The monomer of the helicase contains a AAA+ domain. Each monomer binds and hydrolyzes an ATP in the presence of magnesium and drives an overall conformational change in the hexamer. | + | The monomer of the hexameric helicase contains a AAA+ domain. Each monomer binds and hydrolyzes an ATP in the presence of magnesium ion and drives an overall conformational change in the hexamer. |
Revision as of 02:47, 12 November 2011
Contents |
SV40 Large T Antigen
Introduction
The SV40 large tumor antigen is a multifunctional regulatory protein encoded by Simian Virus 40. It belongs to the AAA+ family of helicases [1]. Noteworthy for its versatility, the protein is responsible for initiation of viral DNA replication, regulation of viral transcription and alteration of the host cell cycle to promote viral infectivity. Large T-antigen is an early gene product of SV40 and is translated after differential mRNA splicing.
Structure
T-antigen consists of an N-terminal J domain, a central origin-binding domain, and a C-terminal helicase domain [1].
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| 1svm, resolution 1.94Å () | |||||||||
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| Ligands: | , , | ||||||||
| Related: | 1svl, 1svo | ||||||||
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| Resources: | FirstGlance, OCA, RCSB, PDBsum | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
Helicase
The monomer of the hexameric helicase contains a AAA+ domain. Each monomer binds and hydrolyzes an ATP in the presence of magnesium ion and drives an overall conformational change in the hexamer.
