1DNF

EFFECTS OF 5-FLUOROURACIL/GUANINE WOBBLE BASE PAIRS IN Z-DNA. MOLECULAR AND CRYSTAL STRUCTURE OF D(CGCGFG)

Summary for 1DNF

• Entry DOI: 10.2210/pdb1dnf/pdb
• Descriptor: DNA (5'-D(*CP*GP*CP*GP*(UFP)P*G)-3'), MAGNESIUM ION (3 entities in total)
• Functional Keywords: z-dna, double helix, modified, mismatched, dna
• Total number of polymer chains: 2
• Total formula weight: 3682.66

Authors

Coll, M.,Saal, D.,Frederick, C.A.,Aymami, J.,Rich, A.,Wang, A.H.-J. (deposition date: 1988-12-12, release date: 1990-10-15, Last modification date: 2024-02-07)

Primary citation

Coll, M.,Saal, D.,Frederick, C.A.,Aymami, J.,Rich, A.,Wang, A.H.
Effects of 5-fluorouracil/guanine wobble base pairs in Z-DNA: molecular and crystal structure of d(CGCGFG).
Nucleic Acids Res., 17:911-923, 1989

PubMed Abstract: The chemotherapeutic agent 5-fluorouracil is a DNA base analogue which is known to incorporate into DNA in vivo. We have solved the structure of the oligonucleotide d(CGCGFG), where F is 5-fluorouracil (5FU). The DNA hexamer crystallizes in the Z-DNA conformation at two pH values with the 5FU forming a wobble base pair with guanine in both crystal forms. No evidence of the enol or ionized form of 5FU is found under either condition. The crystals diffracted X-rays to a resolution of 1.5 A and their structures have been refined to R-factors of 20.0% and 17.2%, respectively, for the pH = 7.0 and pH = 9.0 forms. By comparing this structure to that of d(CGCGCG) and d(CGCGTG), we were able to demonstrate that the backbone conformation of d(CGCGFG) is similar to that of the archetypal Z-DNA. The two F-G wobble base pairs in the duplex are structurally similar to the T-G base pairs both with respect to the DNA helix itself and its interactions with solvent molecules. In both cases water molecules associated with the wobble base pairs bridge between the bases and stabilize the structure. The fluorine in the 5FU base is hydrophobic and is not hydrogen bonded to any solvent molecules.

PubMed: 2922276
DOI: 10.1093/nar/17.3.911

Experimental method

X-RAY DIFFRACTION (1.5 Å)