Figure 2 - Evolution of model systems for proteins and DNA.

(a) Dougherty's host guest system for studying cation- interactions led to Waters' -hairpin peptide for studying N-methylation of cation- interactions in proteins. These model systems provided insight into the importance of the interaction in biological systems, here typified by the HP1 chromodomain bound to trimethyllysine from the H3A histone protein as part of the intact nucleosome. (b) A nonpolar shape mimic of thymidine (dichlorotoluene deoxyriboside; dL), used to study electrostatic and steric effects in DNA replication, is placed into an intact DNA helix (shown here is a DNA structure containing a related compound). This modified DNA is used to gain insight into the function of a DNA polymerase (shown in complex with DNA) in vitro and in E. coli, in which dL was found to be replicated accurately.

Wadsworth Center, New York State Department of Health