User:Udayan Shevade/Sandbox1
From Proteopedia
Contents |
SV40 Large T-Antigen
Introduction
The SV40 large T-antigen is a multifunctional regulatory protein encoded by Simian Virus 40, belonging to the AAA+ family of helicases [1]. It is responsible for initiation of replication, regulation of transcription and alteration of the host cell cycle to promote its infectivity.
Structure
T-antigen consists of an N-terminal J domain, a central origin-binding domain, and a C-terminal helicase domain [1].
The Origin Binding Domain
The central obd monomer consists of five anti-parallel beta sheets flanked on either side by two alpha helices. These molecules arrange tightly into a hexameric left-handed spiral, with 6 obd's per turn. The conformation creates a central channel 60 Angstrom wide, large enough for dsDNA, and is both hydrophobic and highly positively charged [1]. Side-side interaction is crucial in hexamerization, for which residues are crucial. Along the inner surface of the channel, residues implicated in DNA binding are ; ; [1].
