1Y97

The human TREX2 3' exonuclease structure suggests a mechanism for efficient non-processive DNA catalysis

Summary for 1Y97

• Entry DOI: 10.2210/pdb1y97/pdb
• Descriptor: Three prime repair exonuclease 2 (2 entities in total)
• Functional Keywords: trex2, exonuclease, hydrolase
• Biological source: Homo sapiens (human)
• Cellular location: Nucleus (Probable): Q9BQ50
• Total number of polymer chains: 2
• Total formula weight: 52448.69

Authors

Perrino, F.W.,Harvey, S.,McMillin, S.,Hollis, T. (deposition date: 2004-12-14, release date: 2005-01-25, Last modification date: 2024-11-20)

Primary citation

Perrino, F.W.,Harvey, S.,McMillin, S.,Hollis, T.
The Human TREX2 3' -> 5'-Exonuclease Structure Suggests a Mechanism for Efficient Nonprocessive DNA Catalysis.
J.Biol.Chem., 280:15212-15218, 2005

PubMed Abstract: The 3' --> 5'-exonucleases process DNA ends in many DNA repair pathways of human cells. Determination of the human TREX2 structure is the first of a dimeric 3'-deoxyribonuclease and indicates how this highly efficient nonprocessive enzyme removes nucleotides at DNA 3' termini. Symmetry in the TREX2 dimer positions the active sites at opposite outer edges providing open access for the DNA. Adjacent to each active site is a flexible region containing three arginines positioned appropriately to bind DNA and to control its entry into the active site. Mutation of these three arginines to alanines reduces the DNA binding capacity by approximately 100-fold with no effect on catalysis. The human TREX2 catalytic residues overlay with the bacterial DnaQ family of 3'-exonucleases confirming the structural conservation of the catalytic sites despite limited sequence identity, and mutations of these residues decrease the still measurable activity by approximately 10(5)-fold, confirming their catalytic role.

PubMed: 15661738
DOI: 10.1074/jbc.M500108200

Experimental method

X-RAY DIFFRACTION (2.5 Å)