Expression, purification and characterisation of the C-terminal STAS domain of the SLC26 anion transporter prestin.

The membrane protein prestin is the voltage-sensitive molecular motor underlying somatic electromotility of outer hair cells. In order to produce adequate quantities to perform structural and functional studies, we cloned and expressed in bacterial systems three variants of the cytosolic C-terminal STAS domain of prestin from Rattus norvegicus. While the expression level of the longer form of the C-terminal domain (fragment [505-744]) was very low or absent, we succeeded in the overexpression of two shorter fragment of the STAS domain (fragments [529-744], PreCD(L), and [529-720], PreCD(S)).