The TFIIIA recognition fragment d(GGATGGGAG).d(CTCCCATCC) is B-form in solution.
AUTOR(ES)
Aboul-ela, F
RESUMO
The deoxyoligonucleotide d(GGATGGGAG).d(CTCCCATCC) is a portion of the gene recognition sequence of transcription factor IIIA (TFIIIA). The crystal structure of this oligonucleotide was shown to be A-form (Mc Call, M., Brown, T., Hunter, W.N., and Kennard, O. 1986 Nature 322, 661-664). The present study employs NMR, optical, chemical and enzymatic techniques to investigate the solution structure of this DNA 9-mer. NMR COSY experiments indicate 16 of the 18 residues are predominantly south (C2'-endo) sugar conformation. NMR NOESY indicates glycosidic angles in the range predicted for B-form DNA as opposed to A-form. Related DNA and RNA self-complementary 18-mer sequences, d(GGATGGGAGC-TCCCATCC), with U substituted for T in RNA, were studied by circular dichroism. CD spectra support B-form structures for the DNA 9-mer and the DNA 18-mer, and A-form for the RNA 18-mer. High trifluoroethanol concentrations induce a B- to A-form transition in the DNA oligonucleotides. Enzymatic and chemical probes also illustrate significant differences between the DNA and the RNA oligonucleotides. We find no evidence to support an A-form conformation for the TFIIIA recognition sequence d(GGATGGGAG).d(CTCCCATCC) in solution.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=336512Documentos Relacionados
- On the flexibility of the boundaries between the A-form and B-form sections in DNA molecule.
- B-form to A-form conversion by a 3′-terminal ribose: crystal structure of the chimera d(CCACTAGTG)r(G)
- Diepoxybutane forms a monoadduct with B-form (dG-dC)n.(dG-dC)n and a crosslinked diadduct with the left-handed Z-form.
- Conformational flexibility of dinucleoside dimers during unwinding from the B-form to an intercalation structure.
- DNA adopts normal B-form upon incorporation of highly fluorescent DNA base analogue tC: NMR structure and UV-Vis spectroscopy characterization