Protein secondary structure predictions of SRP21, SRP9 and SRP14 proteins. Protein sequences, SRP21 and potential homologs from the organisms indicated as well as human SRP9 and SRP14, were subjected to secondary structure prediction by PSI-PRED . Sequences and predictions are shown unaligned. α-helices and β-strands are indicated by cylinders and arrows, respectively. For human SRP9 and SRP14 the boxed regions indicate the positions of the secondary structure elements as known from the structure of the proteins. The corresponding regions for the fungal proteins are also shown in boxes and are based on the alignment in Fig. 5.