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Updated: Feb 8, 2026

Modification and Functionalization of the Guanidine Group by Tailor-made Precursors
Published on: April 27, 2017
1,3-Di(quinolin-2-yl)guanidine binds to GGCCCC hexanucleotide repeat DNA in C9ORF72
Tomonori Shibata1, Eitaro Murakami1, Kazuhiko Nakatani1
1Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan.
Abstract:
Aberrant expansion of GGGGCC (G4C2) hexanucleotide repeat (HNR) in the first intron of C9ORF72 has been found in frontotemporal dementia and amyotrophic lateral sclerosis (FTD/ALD). The non-canonical DNA structures of the expanded repeats are causative to repeat instability leading to contraction and expansion. We demonstrate that 1,3-di(quinolin-2-yl)guanidine (DQG) binds to GGCCCC/GGCCCC (G2C4/G2C4) motif in double stranded DNA and also antisense G2C4 HNR DNA in C9ORF72. Large increase in the melting temperature of dsDNA containing the G2C4/G2C4 motif was confirmed by the binding of DQG. The marked CD spectral changes indicated structural transition of d(G2C4)9 from i-motifs and/or hairpins to DQG-stabilized d(G2C4)9 structures.
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