Ku protein

(Difference between revisions)

Revision as of 19:04, 3 November 2013

↑ 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

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 == Ku Ring ==
 <scene name='56/567269/Ku_ring/1'>Ku Ring</scene>
-  The Ku ring is composed of a large base that cradles the DNA that consists of beta barrels in the heterodimer, and a narrow bridge that serves to protect the double strand break from base pairing with other DNA base pairs and prevents degradation.  There is little interaction between the ring and the backbone or base pairs of DNA; instead, the ring associates with DNA by the large base 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 Ku ring 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 Ku ring is thin over the bridge, allowing ligases and polymerases to efficiently interact in DNA repair.