Ku protein: Difference between revisions
m Ku Heterodimer moved to Ku protein: requested by Editor |
Michal Harel (talk | contribs) No edit summary |
||
| (2 intermediate revisions by the same user not shown) | |||
| Line 1: | Line 1: | ||
<StructureSection load='1JEY' size=' | <StructureSection load='1JEY' size='350' side='right' caption='Structure of the Ku heterodimer bound to DNA (PDB entry [[1jey]])' scene='56/567269/Ku_heterodimer/4'> | ||
== Overview == | == Overview == | ||
The '''Ku protein''' binds to the ends of double-strand breaks and it is required in DNA-repair for non-homologous end joining. The eukaryotic Ku protein is a | The '''Ku protein''' or '''X-ray repair cross-complementing protein''' binds to the ends of double-strand breaks and it is required in DNA-repair for non-homologous end joining. The eukaryotic Ku protein is a | ||
<scene name='56/567269/Ku_heterodimer/3'>heterodimer</scene> | <scene name='56/567269/Ku_heterodimer/3'>heterodimer</scene> | ||
composed of a | composed of a | ||
<scene name='56/567269/Ku70_subunit/3'>Ku70 subunit</scene> | <scene name='56/567269/Ku70_subunit/3'>Ku70 subunit</scene> or '''X-ray repair cross-complementing protein 6''' | ||
and a <scene name='56/567269/Ku80_subunit/3'>Ku80 subunit</scene> | and a <scene name='56/567269/Ku80_subunit/3'>Ku80 subunit</scene> or '''X-ray repair cross-complementing protein 5''' | ||
. This contributes to genomic integrity through its ability to bind DNA double-strand breaks and facilitate repair by the non-homologous end-joining pathway. The crystal structure of the human Ku heterodimer was determined both alone and | . This contributes to genomic integrity through its ability to bind DNA double-strand breaks and facilitate repair by the non-homologous end-joining pathway. The crystal structure of the human Ku heterodimer was determined both alone and | ||
<scene name='56/567269/Bound_dna/3'>bound to a 55-nucleotide DNA</scene> | <scene name='56/567269/Bound_dna/3'>bound to a 55-nucleotide DNA</scene> | ||
| Line 32: | Line 32: | ||
In terms of protein structure, the α/β-Domain contributes little to the dimer interface between the subunits. | In terms of protein structure, the α/β-Domain contributes little to the dimer interface between the subunits. | ||
The C terminus of the domain can be bound to other repair molecules, using the α/β-Domain as a scaffold.<ref name="Walker"/> | The C terminus of the domain can be bound to other repair molecules, using the α/β-Domain as a scaffold.<ref name="Walker"/> | ||
=== β-barrel === | === β-barrel === | ||
| Line 38: | Line 37: | ||
The <scene name='56/567269/Ku70_dimer/4'>β-barrel</scene> is the main source of interactions of the Ku heterodimer itself and DNA helix, with each β-barrel being composed of seven β strands with the majority in antiparallel arrangement.<ref name="Walker"/> | The <scene name='56/567269/Ku70_dimer/4'>β-barrel</scene> is the main source of interactions of the Ku heterodimer itself and DNA helix, with each β-barrel being composed of seven β strands with the majority in antiparallel arrangement.<ref name="Walker"/> | ||
The quantity of the strands lends the structures to be symmetrical. Both β-barrel in the dimer form the base of the cradle by fitting in the grooves of DNA. | The quantity of the strands lends the structures to be symmetrical. Both β-barrel in the dimer form the base of the cradle by fitting in the grooves of DNA. | ||
=== C-terminal arm === | === C-terminal arm === | ||
| Line 44: | Line 42: | ||
The <scene name='56/567269/Ku70_dimer/7'>C-terminal arm</scene> is an α-helical domain that associates with the β-barrel of the opposite subunit, with the arm stretching across the DNA helix.<ref name="Walker"/> | The <scene name='56/567269/Ku70_dimer/7'>C-terminal arm</scene> is an α-helical domain that associates with the β-barrel of the opposite subunit, with the arm stretching across the DNA helix.<ref name="Walker"/> | ||
As a result, the C-terminal arm strengthens the cradle composed of the two β-barrels. | As a result, the C-terminal arm strengthens the cradle composed of the two β-barrels. | ||
=== DNA binding ring === | === DNA binding ring === | ||
| Line 51: | Line 48: | ||
By binding DNA, Ku realigns the the strands and protects the molecule from degradation and unwanted bonds while NHEJ occurs.<ref name="Walker"/> | By binding DNA, Ku realigns the the strands and protects the molecule from degradation and unwanted bonds while NHEJ occurs.<ref name="Walker"/> | ||
The regulation of the DNA binding ring of Ku is still under research, with data supporting oxidative stress and redox reactions decreasing the association of the Ku heterodimer with bound DNA through alterations in cysteine residues on the Ku70 subunit. <ref name="source3"/> <ref name="source4"> PMID: 14585978</ref> | The regulation of the DNA binding ring of Ku is still under research, with data supporting oxidative stress and redox reactions decreasing the association of the Ku heterodimer with bound DNA through alterations in cysteine residues on the Ku70 subunit. <ref name="source3"/> <ref name="source4"> PMID: 14585978</ref> | ||
== Function == | == Function == | ||
| Line 64: | Line 59: | ||
Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}} | Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}} | ||
[[1jey]] – hKu70 + Ku80 + DNA – human<br /> | [[1jey]], [[5y58]] – hKu70 + Ku80 + DNA – human<br /> | ||
[[1jeq]] – hKu70 + Ku80 <br /> | [[1jeq]] – hKu70 + Ku80 <br /> | ||
[[7axz]] – hKu70 + Ku80 – Cryo EM<br /> | |||
[[6zh6]] – hKu80 + DNA-dependent protein kinase – Cryo EM<br /> | |||
[[7k0y]], [[7k1j]], [[7k1k]], [[7k1n]] – hKu70 + Ku80 + DNA-dependent protein kinase – Cryo EM<br /> | |||
[[6erf]], [[6erg]], [[6erh]] – hKu70 + Ku80 + non-homologous end-joining factor + DNA <br /> | |||
[[1jjr]] – hKu70 C terminal - NMR <br /> | [[1jjr]] – hKu70 C terminal - NMR <br /> | ||
[[1rw2]], [[1q2z]] – hKu80 C terminal - NMR <br /> | [[1rw2]], [[1q2z]] – hKu80 C terminal - NMR <br /> | ||
[[6tyt]], [[6tyu]], [[6tyv]], [[6tyw]], [[6tyx]], [[6tyz]] – hKu80 von Willebrand domain 1-242 (mutant) + peptide <br /> | |||
[[7lt3]] – hKu70 + Ku80 in NHEJ synaptic complex – Cryo EM<br /> | |||
== References== | == References== | ||
<references /> | <references /> | ||
[[Category:Topic Page]] | [[Category:Topic Page]] | ||