NACDDB - The Web Server for DNA,RNA,and Hybrids Circular Dichroism Structure

Sum rules and determination of exciton coupling using absorption and circular dichroism spectra of biological polymers

Overview of Burin AL et al.

AuthorsBurin AL  Armbruster ME  Hariharan M  Lewis FD  
AffiliationDepartment of Chemistry   Tulane University   New Orleans LA 70118   USA. aburin@tulane.edu  
JournalProc Natl Acad Sci U S A
Year 2009

Abstract


Optical spectra of biological polymers contain important information about their structure and function in living organisms. This information can be accessed by extracting an optical interaction of monomers, i.e., their exciton coupling, from experimental data. This coupling is sensitive to molecular structure, geometry, and conformation and can be used to characterize them. However, the accurate determination of exciton coupling in important biological molecules is difficult because inhomogeneous broadening smears out the monomer interaction. We suggest a way to overcome this problem by applying exact sum rules. These sum rules are derived by establishing a straightforward relationship between integral characteristics of absorption and circular dicroism spectra, and exciton coupling. Exciton coupling between AT pairs in native DNA conformation is estimated by applying these sum rules to DNA hairpin optical spectra as V(0) approximately 0.035 eV in agreement with the earlier numerical calculations.