Fig. 1. A secondary structure and topology model of prestin's C-terminus based on a topological model previously described (Zheng et al., 2000). The properties of the amino acids side chains are indicated by different colors for polar (clear), non-polar (blue), acidic (red), basic (green) and cysteine residues (yellow) moieties. The location of the last transmembrane domain is based on the program TMPRED (transmembrane predictions). Regions of the C-terminus with a predicted secondary structure using the program PSIPRED (confidence 6-9) are indicated by colored backgrounds; -helix (blue), coil (red), and strand (green). The STAS domain (gray), and charge clusters (speckled) are indicated by background shading. The locations of the mutations created in prestin mutant proteins examined in this study are indicated with arrows in the cartoon. These include deletion mutants, chimera junction points and double point mutations.