Werner syndrome protein contains three structure-specific DNA binding domains.
Werner syndrome (WS) is a premature aging syndrome caused by mutations in the WS gene (WRN) and a deficiency in the function of the Werner protein (WRN). WRN is a multifunctional nuclear protein that catalyzes three DNA-dependent reactions: a 3'-5'-exonuclease, an ATPase, and a 3'-5'-helicase. Deficiency in WRN results in a cellular phenotype of genomic instability. The biochemical characteristics of WRN and the cellular phenotype of WRN mutants suggest that WRN plays an important role in DNA metabolic pathways such as recombination, transcription, replication, and repair. The catalytic activities of WRN have been extensively studied and are fairly well understood. However, much less is known about the domain-specific interactions between WRN and its DNA substrates. This study identifies and characterizes three distinct WRN DNA binding domains using recombinant truncated fragments of WRN and five DNA substrates (long forked duplex, blunt-ended duplex, single-stranded DNA, 5'-overhang duplex, and Holliday junction). Substrate-specific DNA binding activity was detected in three domains, one N-terminal and two different C-terminal WRN fragments (RecQ conserved domain and helicase RNase D conserved domain-containing domains). The substrate specificity of each DNA binding domain may indicate that each protein domain has a distinct biological function. The importance of these results is discussed with respect to proposed roles for WRN in distinct DNA metabolic pathways.
von Kobbe
Cayetano
C
Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
Thomä
Nicolas H
NH
Czyzewski
Bryan K
BK
Pavletich
Nikola P
NP
Bohr
Vilhelm A
VA
D001665:Binding Sites; D002384:Catalysis; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004265:DNA Helicases / Q000737:chemistry*; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D005090:Exodeoxyribonucleases; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D008957:Models, Genetic; D009154:Mutation; D010641:Phenotype; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D053484:RecQ Helicases; D011994:Recombinant Proteins / Q000737:chemistry; D011995:Recombination, Genetic; D016615:Telomere / Q000648:ultrastructure; D014158:Transcription, Genetic; D000071657:Werner Syndrome Helicase
D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D004247:DNA; D005982:Glutathione Transferase; D005090:Exodeoxyribonucleases; D004265:DNA Helicases; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase