The Iceberg region, downstream the MTase-GTase Core in the alphavirus supergroup. A. Consensus secondary structure of the Iceberg region (which starts after the conserved Y♦ in strand βG) for the alto and tymo groups. Conventions are the same as in Figure 2. Residues conserved in each group are indicated. B. Sequence alignment of the region boxed in A, with the ClustalX coloring scheme . The sequences of the tymo group were aligned to the set alignment of the alto group by using MAFFT with the --add option . Substituted residues Y299 and W222 of BaMV are in bold (see text). Abbreviations: p, polar; h, hydrophobic; s, small.