Shriver Research Laboratory University of Alabama in Huntsville

Gallery of Molecular Graphics Images

NMR solution structure of dimeric Sso10b2, a homolog of Alba. Alba is a chromosomal protein from the Archaea Sulfolobus solfataricus. It is believed to be important in controlling DNA packing. Interestingly, we have recently shown that Sso10b2 shows a higher affinity for single stranded RNA than double stranded DNA. Two different views are shown here, rotated by 90° along the horizontal axis. The structure was refined using NOE, H-bond, and dihedral angle restraints as well as 15N relaxation and residual dipolar coupling data. The principal axis of the rotational diffusion tensor is shown in green, and that of the alignment tensor is in gold.

NMR Solution structure of Sso10a, a DNA binding protein of Sulfolobus solfataricus that is most likely a transcription factor. The structue is a dimer of two winged helices. Dimerization results from the formation of an extended antiparallel coiled coil. Hydrophobic side chains are shown in white, positively charged in blue, and negatively charged in red. An interesting partially buried aspartate occurs at the coiled coil interface and lies within 3Å of a lysine on the adjacent helix to form a salt bridge (one is highlighted in the upper right) which may be important in defining the coiled coil register and stability.

The NMR solution structure of Sac7d. Lysines and arginines are shown in blue, and aspartates and glutamates are shown in red. This view is of the DNA-binding face with the intercalating methionine (M27) and valine (V25) in yellow pointing towards the viewer at the right near the single tryptophan (W24) shown in green.

The structure of a 1:1 Sac7d-DNA complex determined by X-ray crystallography is shown below.

The structure of extended duplex DNA fully saturated with Sac7d determined by small angle X-ray scattering is shown below.