The detection of B-form/A-form junction in a deoxyribonucleotide duplex.
AUTOR(ES)
Ivanov, V I
RESUMO
The transition of the 14-meric deoxyoligonucleotide duplex d-(ACCCCCTTTTTTTG).d-(CAAAAAAAGGGGGT) from the B- to the A-conformation in water/trifluorethanol (TFE) solution was studied with the use of circular dichroism. An increase in the fraction of TFE induces a two-step B-A transition. In the first step, up to 73% TFE, the A-form is generated from the GC-rich part; in the second step, 73-82% TFE, the AT-rich part shifts to the A-form. By this we suggest the existence of a B/A junction near 73% TFE. Emergence of the B/A junction has been directly confirmed with the use of distamycin A and netropsin, ligands known to selectively bind to AT stretches of B-DNA. It can be shown that both ligands suppress formation of the A-form in the B-philic part. The free energy value for the B/A junction was estimated to be 2.1 kcal/mol, which agrees well with known data for polymeric DNAs. The obtained results may have biological relevance in connection with recently published x-ray data about the occurrence of the B/A junction in the complex of DNA with reverse transcriptase of HIV.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1233821Documentos Relacionados
- Inosine.adenine base pairs in a B-DNA duplex.
- Properties of pseudouridine N1 imino protons located in the major groove of an A-form RNA duplex.
- Towards artificial ribonucleases: the sequence-specific cleavage of RNA in a duplex.
- N-acetoxy-2-acetylaminofluorene modification of a deoxyoligonucleotide duplex.
- Structural and dynamic studies of a non-self-complementary dodecamer DNA duplex.