L7S/V8S |
an EYMPE epitope tag is introduced into the interior of Cardiolipin synthase. The tagged polypeptide retains the biological properties of wild type enzyme, including full enzymatic activity. Site-directed mutagenesis is used to alter conserved residues in the N-terminal region. An tagged cardiolipin synthase in which Leu7 and Val8 are both replaced by Ser residues retains in vitro activity but loses most of its in vivo activity. The mutant protein has a higher apparent molecular mass than its parent protein. That conserved residues L7 and V8 play a role in polypeptide processing, topology, or both |
Escherichia coli |