225D
A TETRAMERIC DNA STRUCTURE WITH PROTONATED CYTOSINE:CYTOSINE BASE PAIRS
Summary for 225D
| Entry DOI | 10.2210/pdb225d/pdb |
| Descriptor | DNA (5'-D(*TP*CP*CP*CP*CP*C)-3') (1 entity in total) |
| Functional Keywords | dna, intercalated cytosine tetrad |
| Total number of polymer chains | 4 |
| Total formula weight | 6820.58 |
| Authors | Gehring, K.,Leroy, J.L.,Gueron, M. (deposition date: 1995-07-12, release date: 1995-10-15, Last modification date: 2024-05-22) |
| Primary citation | Gehring, K.,Leroy, J.L.,Gueron, M. A tetrameric DNA structure with protonated cytosine.cytosine base pairs. Nature, 363:561-565, 1993 Cited by PubMed Abstract: Oligomers containing tracts of cytidine form hemiprotonated base pairs at acid pH and have been considered to be double-stranded. We have solved the structure of the DNA oligomer 5'-d(TCCCCC) at acid pH and find that it is a four-stranded complex in which two base-paired parallel-stranded duplexes are intimately associated, with their base pairs fully intercalated. The relative orientation of the duplexes is antiparallel, so that each base pair is face-to-face with its neighbours. The NMR spectrum displays only six spin systems, showing that the structure is highly symmetrical on the NMR timescale; the four strands are equivalent. A model derived by energy minimization and constrained molecular dynamics shows excellent compatibility with the observed nuclear Overhauser effects (NOEs) particularly for the very unusual inter-residue sugar-sugar NOEs H1'-H1', H1'-H2" and H1'-H4'. These NOEs are probably diagnostic for such tetrameric structures. PubMed: 8389423DOI: 10.1038/363561a0 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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