Targeting efficiencies of various permutations of the consensus C-terminal tripeptide peroxisomal targeting signal

Two types of peptide signals are known to independently target proteins into the peroxisomal matrix. One of these is a consensus C-terminal tripeptide which is conserved in many microbody proteins derived from diverse species. The second signal is an N-terminal sequence found in a small subset of peroxisomal proteins. We have tested 18 possible variants of the consensus tripeptide targeting signal for their ability to facilitate the transport of a cytosolic passenger protein, chloramphenicol acetyltransferase, into peroxisomes of monkey kidney cells. Our results reveal the presence of a hierarchy of preferred amino acid substitutions at each position of the tripeptide.