1evo
From Proteopedia
NMR OBSERVATION OF A NOVEL C-TETRAD
Overview
We report the NMR structure of the DNA sequence d-TGGGCGGT in Na(+) solutions at neutral pH, containing a repeat sequence from SV40 viral genome. The structure is a novel quadruplex incorporating the C-tetrad formed by symmetrical pairing of four Cs via NH(2)&bond;O(2) H-bonds in a plane. The C-tetrad has a wider cavity compared to G-tetrads and stacks well over the adjacent G4-tetrad, but poorly on the G6 tetrad. The quadruplex helix is largely underwound by 8-10 degrees compared to B-DNA except at the C5-G6 step. To our knowledge this is the first report of C-tetrad formation in DNA structures, and would be of significance from the point of view of both structural diversity and specific recognition.
About this Structure
Full crystallographic information is available from OCA.
Reference
NMR observation of a novel C-tetrad in the structure of the SV40 repeat sequence GGGCGG., Patel PK, Bhavesh NS, Hosur RV, Biochem Biophys Res Commun. 2000 Apr 21;270(3):967-71. PMID:10772934 Page seeded by OCA on Fri May 2 15:34:29 2008
