5zev
From Proteopedia
Solution structure of G-quadruplex formed in vegfr-2 proximal promoter sequence
Structural highlights
Publication Abstract from PubMedTumor angiogenesis is mainly regulated by vascular endothelial growth factor (VEGF), produced by cancer cells. It is active on the endothelium via VEGF receptor 2 (VEGFR-2). G-quadruplexes are DNA secondary structures formed by guanine-rich sequences, for example, within gene promoters where they may contribute to transcriptional activity. The proximal promoter of vegfr-2 contains a G-quadruplex, which has been suggested to interact with small molecules that inhibit VEGFR-2 expression and thereby tumor angiogenesis. However, its structure is not known. Here, we determined its NMR solution structure, which is composed of three stacked G-tetrads containing three syn guanines. The first guanine (G1) is positioned within the central G-tetrad. We also observed that a noncanonical, V-shaped loop spans three G-tetrad planes, including no bridging nucleotides. A long and diagonal loop, which includes six nucleotides, connects reversal double chains. With a melting temperature of 54.51 degrees C, the scaffold of this quadruplex is stabilized by one G-tetrad plane stacking with one nonstandard base pair, G3-C8, whose bases interact with each other through only one hydrogen bond. In summary, the NMR solution structure of the G-quadruplex in the proximal promoter region of the VEGFR-2 gene reported here has uncovered its key features as a potential anticancer drug target. A putative G-quadruplex structure in the proximal promoter of vegfr-2 has implications for drug design to inhibit tumor angiogenesis.,Liu Y, Lan W, Wang C, Cao C J Biol Chem. 2018 Apr 17. pii: RA118.002666. doi: 10.1074/jbc.RA118.002666. PMID:29666187[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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