The signal that sorts yeast cytochrome b2 to the mitochondrial intermembrane space contains three distinct functional regions.

摘要: Cytochrome b2, a protein of the yeast mitochondrial intermembrane space, is synthesized with an 80 residue bipartite presequence. The amino-terminal portion resembles matrix-targeting signal. carboxy-terminal acts as 'sorting signal' for space and contains hydrophobic stretch. In order to define this sorting signal, we fused first 167 residues cytochrome b2 precursor passenger protein, expressed fusion in selected mutations that caused mislocalization matrix. Most mapped within 81 moiety. They were located three regions, all downstream domain: cluster basic upstream stretch, stretch itself mature b2. level missorting by did not correlate their effects on hydrophobicity, but appeared be related changes conformation We conclude signal decoded protein-protein interactions rather than simple partitioning into lipid bilayer.