|
|
| Line 1: |
Line 1: |
| | | | |
| | ==Crystal Structure of human DNA polymerase gamma accessory subunit== | | ==Crystal Structure of human DNA polymerase gamma accessory subunit== |
| - | <StructureSection load='2g4c' size='340' side='right' caption='[[2g4c]], [[Resolution|resolution]] 3.15Å' scene=''> | + | <StructureSection load='2g4c' size='340' side='right'caption='[[2g4c]], [[Resolution|resolution]] 3.15Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[2g4c]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2G4C OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2G4C FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[2g4c]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2G4C OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2G4C FirstGlance]. <br> |
| - | </td></tr><tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">POLG2, MTPOLB ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr> | + | </td></tr><tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">POLG2, MTPOLB ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 HUMAN])</td></tr> |
| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/DNA-directed_DNA_polymerase DNA-directed DNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.7 2.7.7.7] </span></td></tr> | + | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/DNA-directed_DNA_polymerase DNA-directed DNA polymerase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.7 2.7.7.7] </span></td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2g4c FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2g4c OCA], [http://pdbe.org/2g4c PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2g4c RCSB], [http://www.ebi.ac.uk/pdbsum/2g4c PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2g4c ProSAT]</span></td></tr> | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2g4c FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2g4c OCA], [https://pdbe.org/2g4c PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2g4c RCSB], [https://www.ebi.ac.uk/pdbsum/2g4c PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2g4c ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Disease == | | == Disease == |
| - | [[http://www.uniprot.org/uniprot/DPOG2_HUMAN DPOG2_HUMAN]] Defects in POLG2 are the cause of progressive external ophthalmoplegia with mitochondrial DNA deletions autosomal dominant type 4 (PEOA4) [MIM:[http://omim.org/entry/610131 610131]]. Progressive external ophthalmoplegia is characterized by progressive weakness of ocular muscles and levator muscle of the upper eyelid. In a minority of cases, it is associated with skeletal myopathy, which predominantly involves axial or proximal muscles and which causes abnormal fatigability and even permanent muscle weakness. Ragged-red fibers and atrophy are found on muscle biopsy. A large proportion of chronic ophthalmoplegias are associated with other symptoms, leading to a multisystemic pattern of this disease. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism.<ref>PMID:16685652</ref> | + | [[https://www.uniprot.org/uniprot/DPOG2_HUMAN DPOG2_HUMAN]] Defects in POLG2 are the cause of progressive external ophthalmoplegia with mitochondrial DNA deletions autosomal dominant type 4 (PEOA4) [MIM:[https://omim.org/entry/610131 610131]]. Progressive external ophthalmoplegia is characterized by progressive weakness of ocular muscles and levator muscle of the upper eyelid. In a minority of cases, it is associated with skeletal myopathy, which predominantly involves axial or proximal muscles and which causes abnormal fatigability and even permanent muscle weakness. Ragged-red fibers and atrophy are found on muscle biopsy. A large proportion of chronic ophthalmoplegias are associated with other symptoms, leading to a multisystemic pattern of this disease. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism.<ref>PMID:16685652</ref> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/DPOG2_HUMAN DPOG2_HUMAN]] Mitochondrial polymerase processivity subunit. Stimulates the polymerase and exonuclease activities, and increases the processivity of the enzyme. Binds to ss-DNA. | + | [[https://www.uniprot.org/uniprot/DPOG2_HUMAN DPOG2_HUMAN]] Mitochondrial polymerase processivity subunit. Stimulates the polymerase and exonuclease activities, and increases the processivity of the enzyme. Binds to ss-DNA. |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
| | Check<jmol> | | Check<jmol> |
| | <jmolCheckbox> | | <jmolCheckbox> |
| - | <scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/g4/2g4c_consurf.spt"</scriptWhenChecked> | + | <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/g4/2g4c_consurf.spt"</scriptWhenChecked> |
| | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> |
| | <text>to colour the structure by Evolutionary Conservation</text> | | <text>to colour the structure by Evolutionary Conservation</text> |
| Line 37: |
Line 37: |
| | [[Category: DNA-directed DNA polymerase]] | | [[Category: DNA-directed DNA polymerase]] |
| | [[Category: Human]] | | [[Category: Human]] |
| | + | [[Category: Large Structures]] |
| | [[Category: Fan, L]] | | [[Category: Fan, L]] |
| | [[Category: Farr, C L]] | | [[Category: Farr, C L]] |
| Structural highlights
Disease
[DPOG2_HUMAN] Defects in POLG2 are the cause of progressive external ophthalmoplegia with mitochondrial DNA deletions autosomal dominant type 4 (PEOA4) [MIM:610131]. Progressive external ophthalmoplegia is characterized by progressive weakness of ocular muscles and levator muscle of the upper eyelid. In a minority of cases, it is associated with skeletal myopathy, which predominantly involves axial or proximal muscles and which causes abnormal fatigability and even permanent muscle weakness. Ragged-red fibers and atrophy are found on muscle biopsy. A large proportion of chronic ophthalmoplegias are associated with other symptoms, leading to a multisystemic pattern of this disease. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism.[1]
Function
[DPOG2_HUMAN] Mitochondrial polymerase processivity subunit. Stimulates the polymerase and exonuclease activities, and increases the processivity of the enzyme. Binds to ss-DNA.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Mitochondrial DNA polymerase (pol gamma) is the sole DNA polymerase responsible for replication and repair of animal mitochondrial DNA. Here, we address the molecular mechanism by which the human holoenzyme achieves high processivity in nucleotide polymerization. We have determined the crystal structure of human pol gamma-beta, the accessory subunit that binds with high affinity to the catalytic core, pol gamma-alpha, to stimulate its activity and enhance holoenzyme processivity. We find that human pol gamma-beta shares a high level of structural similarity to class IIa aminoacyl tRNA synthetases, and forms a dimer in the crystal. A human pol gamma/DNA complex model was developed using the structures of the pol gamma-beta dimer and the bacteriophage T7 DNA polymerase ternary complex, which suggests multiple regions of subunit interaction between pol gamma-beta and the human catalytic core that allow it to encircle the newly synthesized double-stranded DNA, and thereby enhance DNA binding affinity and holoenzyme processivity. Biochemical properties of a novel set of human pol gamma-beta mutants are explained by and test the model, and elucidate the role of the accessory subunit as a novel type of processivity factor in stimulating pol gamma activity and in enhancing processivity.
A novel processive mechanism for DNA synthesis revealed by structure, modeling and mutagenesis of the accessory subunit of human mitochondrial DNA polymerase.,Fan L, Kim S, Farr CL, Schaefer KT, Randolph KM, Tainer JA, Kaguni LS J Mol Biol. 2006 May 19;358(5):1229-43. Epub 2006 Mar 15. PMID:16574152[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Longley MJ, Clark S, Yu Wai Man C, Hudson G, Durham SE, Taylor RW, Nightingale S, Turnbull DM, Copeland WC, Chinnery PF. Mutant POLG2 disrupts DNA polymerase gamma subunits and causes progressive external ophthalmoplegia. Am J Hum Genet. 2006 Jun;78(6):1026-34. Epub 2006 May 4. PMID:16685652 doi:S0002-9297(07)63923-8
- ↑ Fan L, Kim S, Farr CL, Schaefer KT, Randolph KM, Tainer JA, Kaguni LS. A novel processive mechanism for DNA synthesis revealed by structure, modeling and mutagenesis of the accessory subunit of human mitochondrial DNA polymerase. J Mol Biol. 2006 May 19;358(5):1229-43. Epub 2006 Mar 15. PMID:16574152 doi:http://dx.doi.org/10.1016/j.jmb.2006.02.073
|
