3qe9: Difference between revisions
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<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=3qe9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3qe9 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3qe9 RCSB], [http://www.ebi.ac.uk/pdbsum/3qe9 PDBsum]</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=3qe9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3qe9 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3qe9 RCSB], [http://www.ebi.ac.uk/pdbsum/3qe9 PDBsum]</span></td></tr> | ||
</table> | </table> | ||
== Function == | |||
[[http://www.uniprot.org/uniprot/EXO1_HUMAN EXO1_HUMAN]] 5'->3' double-stranded DNA exonuclease which may also possess a cryptic 3'->5' double-stranded DNA exonuclease activity. Functions in DNA mismatch repair (MMR) to excise mismatch-containing DNA tracts directed by strand breaks located either 5' or 3' to the mismatch. Also exhibits endonuclease activity against 5'-overhanging flap structures similar to those generated by displacement synthesis when DNA polymerase encounters the 5'-end of a downstream Okazaki fragment. Required for somatic hypermutation (SHM) and class switch recombination (CSR) of immunoglobulin genes. Essential for male and female meiosis.<ref>PMID:10364235</ref> <ref>PMID:10608837</ref> <ref>PMID:11809771</ref> <ref>PMID:11842105</ref> <ref>PMID:12414623</ref> <ref>PMID:12704184</ref> <ref>PMID:14636568</ref> <ref>PMID:14676842</ref> <ref>PMID:15225546</ref> <ref>PMID:15886194</ref> <ref>PMID:16143102</ref> <ref>PMID:9685493</ref> | |||
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== Publication Abstract from PubMed == | == Publication Abstract from PubMed == |
Revision as of 11:46, 24 December 2014
Crystal structure of human exonuclease 1 Exo1 (D173A) in complex with DNA (complex I)Crystal structure of human exonuclease 1 Exo1 (D173A) in complex with DNA (complex I)
Structural highlights
Function[EXO1_HUMAN] 5'->3' double-stranded DNA exonuclease which may also possess a cryptic 3'->5' double-stranded DNA exonuclease activity. Functions in DNA mismatch repair (MMR) to excise mismatch-containing DNA tracts directed by strand breaks located either 5' or 3' to the mismatch. Also exhibits endonuclease activity against 5'-overhanging flap structures similar to those generated by displacement synthesis when DNA polymerase encounters the 5'-end of a downstream Okazaki fragment. Required for somatic hypermutation (SHM) and class switch recombination (CSR) of immunoglobulin genes. Essential for male and female meiosis.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] Publication Abstract from PubMedHuman exonuclease 1 (hExo1) plays important roles in DNA repair and recombination processes that maintain genomic integrity. It is a member of the 5' structure-specific nuclease family of exonucleases and endonucleases that includes FEN-1, XPG, and GEN1. We present structures of hExo1 in complex with a DNA substrate, followed by mutagenesis studies, and propose a common mechanism by which this nuclease family recognizes and processes diverse DNA structures. hExo1 induces a sharp bend in the DNA at nicks or gaps. Frayed 5' ends of nicked duplexes resemble flap junctions, unifying the mechanisms of endo- and exonucleolytic processing. Conformational control of a mobile region in the catalytic site suggests a mechanism for allosteric regulation by binding to protein partners. The relative arrangement of substrate binding sites in these enzymes provides an elegant solution to a complex geometrical puzzle of substrate recognition and processing. Structures of human exonuclease 1 DNA complexes suggest a unified mechanism for nuclease family.,Orans J, McSweeney EA, Iyer RR, Hast MA, Hellinga HW, Modrich P, Beese LS Cell. 2011 Apr 15;145(2):212-23. PMID:21496642[13] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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