FIG. 4.

Secondary-structure predictions of domains C and D are consistent with an OB fold. Amino acid sequences of domains C and D from yeast and humans were analyzed by the Predict Protein program, European Molecular Biology Laboratory, Heidelberg, Germany (48). The predicted secondary structures of domains C (A) and D (B) are displayed above the yeast (scRPA1C and scRPA2, respectively) and below the human (hsRPA1C and hsRPA2, respectively) sequences. The sequence of the Cys₄ motif (A) and the three highly conserved residues within each amino acid sequence (A and B) are highlighted in white type on a black background. The proposed β strands of the OB fold are indicated. H, helix; E, extended β-sheet.