Ku protein
From Proteopedia
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The <scene name='56/567269/Ku_ring/1'>Ku Ring</scene> is composed of a broad base of beta barrels that cradle the DNA, and a narrow bridge that serves to protect the double strand break from base pairing with other DNA base pairs and degradation. There is little interaction between the ring and the backbone or base pairs of DNA; instead, the ring associates with DNA by the cradle fitting into the major grooves of the helix. The positive electrostatic charge caused by polarization of the ring also allows the negatively charged backbone of DNA to be guided into the correct position. The Ku protein also has a high affinity to DNA due to its form being preset for the helix. As a result of the asymmetric ring, there is a strong preference (Kd value of 1.5 to 4 X 10^-10 M) for the <scene name='56/567269/Ku_ring/1'>Ku Ring</scene> to slide onto the ends of DNA. In addition, other asymmetric features prevent the Ku protein from sliding further on the DNA helix. While wrapping over the entire helix, the <scene name='56/567269/Ku_ring/1'>Ku Ring</scene> is thin over the bridge, allowing ligases and polymerases to efficiently interact in [[non-homologous end joining (NHEJ)]]. <ref> PMID: 11493912</ref> | The <scene name='56/567269/Ku_ring/1'>Ku Ring</scene> is composed of a broad base of beta barrels that cradle the DNA, and a narrow bridge that serves to protect the double strand break from base pairing with other DNA base pairs and degradation. There is little interaction between the ring and the backbone or base pairs of DNA; instead, the ring associates with DNA by the cradle fitting into the major grooves of the helix. The positive electrostatic charge caused by polarization of the ring also allows the negatively charged backbone of DNA to be guided into the correct position. The Ku protein also has a high affinity to DNA due to its form being preset for the helix. As a result of the asymmetric ring, there is a strong preference (Kd value of 1.5 to 4 X 10^-10 M) for the <scene name='56/567269/Ku_ring/1'>Ku Ring</scene> to slide onto the ends of DNA. In addition, other asymmetric features prevent the Ku protein from sliding further on the DNA helix. While wrapping over the entire helix, the <scene name='56/567269/Ku_ring/1'>Ku Ring</scene> is thin over the bridge, allowing ligases and polymerases to efficiently interact in [[non-homologous end joining (NHEJ)]]. <ref> PMID: 11493912</ref> | ||
== Domains == | == Domains == | ||
| - | <scene name='56/567269/ | + | <scene name='56/567269/Ku70_dimer/1'>Ku70 Dimer</scene> |
| - | Consisting of three domains (Alpha/Beta, Beta barrel, C-terminal, the <scene name='56/567269/ | + | Consisting of three domains (Alpha/Beta, Beta barrel, C-terminal, the <scene name='56/567269/Ku70_dimer/1'>Ku70 Dimer</scene> is dimerized with the <scene name='56/567269/Ku80_subunit/3'>Ku80</scene> the A 70 kD component of the protein, the <scene name='56/567269/Ku70_domain/1'>Ku70 Domain</scene> serves as the main place of interaction with DNA. |
<scene name='56/567269/Ku70_dimer/2'>α/β-Domain</scene> | <scene name='56/567269/Ku70_dimer/2'>α/β-Domain</scene> | ||
Revision as of 19:34, 3 November 2013
Structure of the Ku heterodimer bound to DNA
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References
- ↑ Walker JR, Corpina RA, Goldberg J. Structure of the Ku heterodimer bound to DNA and its implications for double-strand break repair. Nature. 2001 Aug 9;412(6847):607-14. PMID:11493912 doi:10.1038/35088000
- ↑ Walker JR, Corpina RA, Goldberg J. Structure of the Ku heterodimer bound to DNA and its implications for double-strand break repair. Nature. 2001 Aug 9;412(6847):607-14. PMID:11493912 doi:10.1038/35088000
