کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1952552 | 1057214 | 2009 | 9 صفحه PDF | دانلود رایگان |
The B-cell lymphoma-2 (bcl-2) gene contains a region that has been implicated in the regulation of bcl-2 gene expression. This region can form G-quadruplex structures in solution [J.X. Dai, T.S. Dexheimer, D. Chen, M. Carver, A. Ambrus, R.A. Jones, D.Z. Yang, An intramolecular G-quadruplex structure with mixed parallel/antiparallel G-strands formed in the human BCL-2 promoter region in solution, J. Am. Chem. Soc. 128 (2006) 1096–1098.]. Here, we examined the acid–base and conformational equilibria of this G-quadruplex-forming region (BCL2G), as well as its interaction with both the porphyrin TMPyP4 and with the complementary C-rich strand. We used molecular absorption and circular dichroism techniques, in tandem with multivariate analysis tools. The results revealed the formation of an interaction complex BCL2G:TMPyP4 with a stoichiometry of 1:2 and an equilibrium constant equal to 5.0 (±2.3) × 1013 M−2. Addition of the complementary C-rich strand to BCL2G induces the predominant formation of the Watson–Crick double-helix with an equilibrium constant equal to 107.7 M−1 (at pH 7.1). Finally, the pH-induced formation of quadruplex structures from the Watson–Crick double-helix is characterized.
Journal: Biochimie - Volume 91, Issue 7, July 2009, Pages 894–902