Jun-Huei Fan - Circular dichroism spectra and electrophoretic mobility shift assays show that human replication protein A binds and melts intramolecular G-quadruplex structures

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      Publication Details (including relevant citation   information):

      Biochemistry. 2009 Feb 10;48(5):1099-111

      This article has been cited by 1 ACS Journal articles:

      A Small Molecule That Disrupts G-Quadruplex DNA Structure and   Enhances Gene Expression

      Zo  A. E. Waller, Sven A. Sewitz, Shang-Te Danny Hsu and Shankar   Balasubramanian

      Journal of the American Chemical   Society2009 131 (35),   12628-12633

     

      Abstract:

      Noncanonical DNA structures such as G-quadruplexes might obstruct   the binding of hRPA, compromising the accuracy of replication,   and be a source of genomic instability. In this study, circular   dichroism (CD) and electrophoretic mobility shift assay (EMSA)   experiments were used to show that hRPA can bind and melt   nontelomeric, intramolecular DNA G-quadruplexes under   physiologically germane conditions. EMSA results show that hRPA   binds to a 58-mer that includes an embedded quadruplex with an   affinity equal to or greater than to nonquadruplex forming   58-mers. Moreover, hRPA binds to a 26-mer purine-rich   quadruplex-forming sequence with an affinity indistinguishable   from that for binding to the complementary pyrimidine-rich   sequence. Under the same conditions, hRPA does not have   significant affinity for binding to the duplex formed from the   two sequences. Thus, DNA secondary structures can significantly   modulate the binding affinity of hRPA over and above its known   preference for pyrimidine-rich single-stranded sequences, so that   at least some intramolecular G-quadruplex structures may not   inhibit hRPA binding during DNA replication. CD spectral changes   in combination with EMSA titrations suggest that one hRPA   heterotrimer is sufficient to form a stable complex with an   unfolded 26-mer G-quadruplex prior to the binding of a second   hRPA molecule.

      Address (URL): http://pubs.acs.org/doi/abs/10.1021/bi801538h