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Purification, characterization and molecular cloning of TGP1, a novel G-DNA binding protein from Tetrahymena thermophila
Nucleic Acids Research
  • Quan Lu, Iowa State University
  • Ted Schierer, Iowa State University
  • Sang-Gu Kang, Iowa State University
  • Eric Henderson, Iowa State University
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G-DNA, a polymorphic family of four-stranded DNA structures, has been proposed to play roles in a variety of biological processes including telomere function, meiotic recombination and gene regulation. Here we report the purification and cloning of TGP1, a G-DNA specific binding protein from Tetrahymena thermophila. TGP1 was purified by three-column chromatographies, including a G-DNA affinity column. Two major proteins (∼80 and ∼40 kDa) were present in the most highly purified column fraction. Renaturation experiments showed that the ∼80 kDa protein contains TGP1 activity. Biochemical characterization showed that TGP1 is a G-DNA specific binding protein with a preference for parallel G-DNAs. The TGP1/DNA complex has a dissociation constant (Kd) of ∼2.2 ×10−8 M and TGP1 can form supershift in gel mobility shift assays. The cDNA coding TGP1 was cloned and sequenced based upon an internal peptide sequence obtained from the ∼80 kDa protein. Sequence analyses showed that TGP1 is a basic protein with a pI of 10.58, and contains two extensively hydrophilic and basic domains. Homology searches revealed that TGP1 is a novel protein sharing weak similarities with a number of proteins.

This article is from Nucleic Acids Research 26 (1998): 1613, doi: 10.1093/nar/26.7.1613. Posted with permission.

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Oxford University Press
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Quan Lu, Ted Schierer, Sang-Gu Kang and Eric Henderson. "Purification, characterization and molecular cloning of TGP1, a novel G-DNA binding protein from Tetrahymena thermophila" Nucleic Acids Research Vol. 26 Iss. 7 (1998) p. 1613 - 1620
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