Biophysical Journal 85 5

Cover: Overlay of C-α backbones of the HH26-HEL model and HH26-HEL crystal structure. The HH26-HEL structure was homology modeled using the HH10-HEL x-ray coordinates (Padlan et al., 1989; Proc. Natl. Acad. Sci. USA. 86:5938–5942, PDB accession code 3HFM) as a template. Crystal structure (Li et al., 2003; Nature Struct. Biol. 10:482–488, PDB accession code 1NDM) is shown in red, and the model in green. The two structures show a high degree of similarity, with RMSD of 1.03 Å, within the resolution of the H26 x-ray crystal structure. These results demonstrate that homology modeling combined with energy minimization of a lower resolution structure can predict a structure and atomic interactions of a closely related protein that compares well to its higher resolution x-ray structure. Illustration generated using INSIGHT II package (Accelrys Inc.). See the article by Mohan et al. on p. 3221.