Science at the Edge seminar speaker Dr. Hashim Al-Hashimi, Dept. of Chemistry & Biophysics, University of Michigan is rescheduled to give his talk on Friday, April 15.  There are several afternoon appointment slots available and if you would like to meet with Dr. Al-Hashimi, please reply to this message with your available times.  His abstract follows this message.

 

Thank you.

Helen

 

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

E-mail: [log in to unmask]

Web: http://qbmi.msu.edu

http://www.bch.msu.edu/GEDD/index.htm

 

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.