Details

Autor(en) / Beteiligte

• Aishima, Jun
• Gitti, Rossitza K
• Noah, Joyce E
• Gan, Hin Hark
• Schlick, Tamar
• Wolberger, Cynthia

Titel

A Hoogsteen base pair embedded in undistorted B-DNA

Ist Teil von

• Nucleic acids research, 2002-12, Vol.30 (23), p.5244-5252

Ort / Verlag

England

Erscheinungsjahr

2002

Quelle

MEDLINE

Beschreibungen/Notizen

• Hoogsteen base pairs within duplex DNA typically are only observed in regions containing significant distortion or near sites of drug intercalation. We report here the observation of a Hoogsteen base pair embedded within undistorted, unmodified B-DNA. The Hoogsteen base pair, consisting of a syn adenine base paired with an anti thymine base, is found in the 2.1 A resolution structure of the MATalpha2 homeodomain bound to DNA in a region where a specifically and a non-specifically bound homeodomain contact overlapping sites. NMR studies of the free DNA show no evidence of Hoogsteen base pair formation, suggesting that protein binding favors the transition from a Watson-Crick to a Hoogsteen base pair. Molecular dynamics simulations of the homeodomain-DNA complex support a role for the non-specifically bound protein in favoring Hoogsteen base pair formation. The presence of a Hoogsteen base pair in the crystal structure of a protein-DNA complex raises the possibility that Hoogsteen base pairs could occur within duplex DNA and play a hitherto unrecognized role in transcription, replication and other cellular processes.