RTP and Tus: Difference between revisions

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The structure of Tus is unusual for a DNA-binding protein. It binds ''Ter'' DNA as an asymmetrical monomer, which establishes the basis for its polar arrest of the replication fork. Tus has three distinct regions: two α-helical regions and central β-strands which jointly form a large, positively-charged central cleft (Kamada, 1996). The core β-structures embrace 13 base pairs of duplex DNA by partial insertion into the major groove, and at least 30 other residues make nonspecific contacts with the DNA backbone.

The positioning of α-helices in the Tus protein is particularly interesting. Two protrude from both the amino and carboxy domains to clasp the DNA duplex, thereby shielding the interdomain β structures from direct contacts with other proteins (such as the DnaB helicase). The concentration of α-helices on the non-permissive face of Tus is absolutely cruical to the protein's ability to form a locked complex with the ''Ter'' site. More about this later!

RTP and Tus: Difference between revisions

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Revision as of 10:14, 13 May 2011 view source Rada Germanos (talk \| contribs) 146 edits No edit summary ← Older edit		Revision as of 10:14, 13 May 2011 view source Rada Germanos (talk \| contribs) 146 edits No edit summary Newer edit →
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	The structure of Tus is unusual for a DNA-binding protein. It binds ''Ter'' DNA as an asymmetrical monomer, which establishes the basis for its polar arrest of the replication fork. Tus has three distinct regions: two α-helical regions and central β-strands which jointly form a large, positively-charged central cleft (Kamada, 1996). The core β-structures embrace 13 base pairs of duplex DNA by partial insertion into the major groove, and at least 30 other residues make nonspecific contacts with the DNA backbone.		The structure of Tus is unusual for a DNA-binding protein. It binds ''Ter'' DNA as an asymmetrical monomer, which establishes the basis for its polar arrest of the replication fork. Tus has three distinct regions: two α-helical regions and central β-strands which jointly form a large, positively-charged central cleft (Kamada, 1996). The core β-structures embrace 13 base pairs of duplex DNA by partial insertion into the major groove, and at least 30 other residues make nonspecific contacts with the DNA backbone.
	The positioning of α-helices in the Tus protein is particularly interesting. Two protrude from both the amino and carboxy domains to clasp the DNA duplex, thereby shielding the interdomain β structures from direct contacts with other proteins (such as the DnaB helicase). The concentration of α-helices on the non-permissive face of Tus is absolutely cruical to the protein's ability to form a locked complex with the ''Ter'' site. More about this later!		The positioning of α-helices in the Tus protein is particularly interesting. Two protrude from both the amino and carboxy domains to clasp the DNA duplex, thereby shielding the interdomain β structures from direct contacts with other proteins (such as the DnaB helicase). The concentration of α-helices on the non-permissive face of Tus is absolutely cruical to the protein's ability to form a locked complex with the ''Ter'' site. More about this later!