Fig. 2.

Atomic models of T4 gp20 portal protein. Models (a) to (e) were computed by combinations of a threading method, a comparative modeling, followed by residue-based and atom-based refinements. Model f was generated by a comparative modeling method using SwissModel server. The colors indicate the position of residues in the polypeptide chain, transitioning from blue at the N-terminus (aa 250) to red at the C-terminus (aa 512). The N- and C-termini of model (a) are marked with blue and red dots respectively, and the amino acid numbers of the termini are also shown. The same applies to all other models (b) to (f) shown in the figure. See Materials and Methods for details of model building.