SCIENCE AT THE EDGE SEMINAR
QB/GEDD
Friday, February 25 at 11:30am
Room 1400 Biomedical and Physical Sciences Bldg.
Refreshments at 11:15
Hashim M. Al-Hashimi
Department of Chemistry and Biophysics, University of Michigan
The Nucleic Acid Dance at Atomic-Resolution
NMR data and computational molecular dynamics simulations are combined to yield a 3D atomic view of thermal fluctuations in nucleic acids over timescales spanning picoseconds to milliseconds. Detailed analysis
of RNA dynamic trajectories reveals spatially choreographed movements within a pre-confined space in which helices linked by two-way junctions twist in a synchronized manner while simultaneously bending. The spatial choreography of the dynamics is a universal
and fundamental feature of RNA structure, which arises from topological constraints encoded at the secondary structure level. A combined NMR-computational analysis reveals that simple DNA duplexes undergo excursions outside the Watson-Crick framework towards
Hoogsteen base pairs that are transiently (<1%) sampled ubiquitously across all CA steps at slow micro-to-millisecond timescales. The observation of Hoogsteen base pairs in duplex DNAs bound to proteins and in the context of damaged DNA suggest that DNA sequences
code for excited-state structures that could provide yet another layer of genetic information.
Helen Geiger
Administrative Assistant
Quantitative Biology Graduate Program/
Gene Expression in Development & Disease
Michigan State University
502B Biochemistry Building
East Lansing, MI 48824
Phone: (517) 432-9895
Fax: (517) 353-9334
Web: http://qbmi.msu.edu
http://www.bch.msu.edu/GEDD/index.htm