A sequence correlation between oppositely charged residues in secreted proteins

Amino acid sequences of 14 secreted proteins have been secreened for correlations between the relative positions of oppositely charged residues. The results show that arginine residues belonging to a particular class of chain segments have glutamic or aspartic acid residues situated four positions away in the sequence significantly more often than expected by chance. This finding is discussed in the light of various models for the trans-membrane translocation process.