Modulation of Werner syndrome protein function by a single mutation in the conserved RecQ domain.
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.
Lee
Jae Wan
JW
Laboratory of Molecular Gerontology, NIA, National Institutes of Health, Baltimore, Maryland 21224-6825, USA.
Kusumoto
Rika
R
Doherty
Kevin M
KM
Lin
Guang-Xin
GX
Zeng
Wangyong
W
Cheng
Wen-Hsing
WH
von Kobbe
Cayetano
C
Brosh
Robert M
RM
Hu
Jin-Shan
JS
Bohr
Vilhelm A
VA
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D017124:Conserved Sequence; D004247:DNA / Q000235:genetics; D004265:DNA Helicases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D005090:Exodeoxyribonucleases; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D020125:Mutation, Missense; D019906:Nuclear Magnetic Resonance, Biomolecular; D017434:Protein Structure, Tertiary; D053484:RecQ Helicases; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014898:Werner Syndrome / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D000071657:Werner Syndrome Helicase
D011994:Recombinant Proteins; D004247:DNA; D005090:Exodeoxyribonucleases; D000251:Adenosine Triphosphatases; C506725:RECQL protein, human; D004265:DNA Helicases; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase