1. Modulation of Werner Syndrome Protein Function by a Single Mutation in the Conserved RecQ Domain
- Author
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Jin-Shan Hu, Guang-Xin Lin, Robert M. Brosh, Jae Wan Lee, Kevin M. Doherty, Wen-Hsing Cheng, Cayetano von Kobbe, Wangyong Zeng, Rika Kusumoto, and Vilhelm A. Bohr
- Subjects
Premature aging ,congenital, hereditary, and neonatal diseases and abnormalities ,Werner Syndrome Helicase ,DNA repair ,Amino Acid Motifs ,Molecular Sequence Data ,Mutation, Missense ,In Vitro Techniques ,Biology ,medicine.disease_cause ,Biochemistry ,Cell Line ,medicine ,Holliday junction ,Humans ,Amino Acid Sequence ,Nuclear Magnetic Resonance, Biomolecular ,Molecular Biology ,Conserved Sequence ,Werner syndrome ,Adenosine Triphosphatases ,Genetics ,Mutation ,Base Sequence ,RecQ Helicases ,Sequence Homology, Amino Acid ,Mutagenesis ,DNA Helicases ,DNA replication ,nutritional and metabolic diseases ,Helicase ,DNA ,Cell Biology ,medicine.disease ,Recombinant Proteins ,Protein Structure, Tertiary ,Exodeoxyribonucleases ,Mutagenesis, Site-Directed ,biology.protein ,Werner Syndrome - Abstract
Naturally occurring mutations in the human RECQ3 gene result in truncated Werner protein (WRN) and manifest as a rare premature aging disorder, Werner syndrome. Cellular and biochemical studies suggest a multifaceted role of WRN in DNA replication, DNA repair, recombination, and telomere maintenance. The RecQ C-terminal (RQC) domain of WRN was determined previously to be the major site of interaction for DNA and proteins. By using site-directed mutagenesis in the WRN RQC domain, we determined which amino acids might be playing a critical role in WRN function. A site-directed mutation at Lys-1016 significantly decreased WRN binding to fork or bubble DNA substrates. Moreover, the Lys-1016 mutation markedly reduced WRN helicase activity on fork, D-loop, and Holliday junction substrates in addition to reducing significantly the ability of WRN to stimulate FEN-1 incision activities. Thus, DNA binding mediated by the RQC domain is crucial for WRN helicase and its coordinated functions. Our nuclear magnetic resonance data on the three-dimensional structure of the wild-type RQC and Lys-1016 mutant proteins display a remarkable similarity in their structures.
- Published
- 2005