Sandbox20: Difference between revisions
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It is known with some certainty that the RTP dimer adopts an asymmetric arrangement upon binding of the TerB site. <ref>PMID: 17521668</ref> In the [[2efw| C110S mutant]] complexed with the native TerB sequence, the two subunits interact differently with the DNA bases to produce wing-up and wing-down conformations.<ref>PMID: 14559228</ref> These can be distinguished by the angle the α2 helix makes with the α3 helix indicated in this <scene name='Sandbox20/2efw/14'>model</scene>. It is likely that asymmetry is also introduced when the RTP dimer binds to the TerA site, but the crystal structure of this complex has not been solved. | It is known with some certainty that the RTP dimer adopts an asymmetric arrangement upon binding of the TerB site. <ref>PMID: 17521668</ref> In the [[2efw| C110S mutant]] complexed with the native TerB sequence, the two subunits interact differently with the DNA bases to produce wing-up and wing-down conformations.<ref>PMID: 14559228</ref> These can be distinguished by the angle the α2 helix makes with the α3 helix indicated in this <scene name='Sandbox20/2efw/14'>model</scene>. It is likely that asymmetry is also introduced when the RTP dimer binds to the TerA site, but the crystal structure of this complex has not been solved. | ||
The dissociation constant of the RTP-TerA complex is greater than that of RTP-TerB, indicating an inherently a lower binding affinity.<ref>PMID: 17521668</ref> However, following the binding of RTP to TerA, a positive cooperative effect facilitates the binding of RTP to TerA. | The dissociation constant of the RTP-TerA complex is greater than that of RTP-TerB, indicating an inherently a lower binding affinity.<ref>PMID: 17521668</ref> However, following the binding of RTP to TerA, a positive cooperative effect facilitates the binding of RTP to TerA.<ref>PMID: 7867072</ref> It has been proposed that RTP bends the DNA at the TerB site in a manner that favours RTP binding at TerA. The RTP dimer at TerB may also present a surface for stabilising interactions with the dimer at TerA through its β1 loop and β3 strand. | ||
=== Replication Termination Activity=== | === Replication Termination Activity=== | ||