Proteins Sequence sites, features and motifs Protein sites, features and motifs 1.8 Protein_sites_features_and_motifs A signal peptide coding sequence encodes an N-terminal domain of a secreted protein, which is involved in attaching the polypeptide to a membrane leader sequence. A transit peptide coding sequence encodes an N-terminal domain of a nuclear-encoded organellar protein; which is involved in import of the protein into the organelle. Protein sequence features The biology, archival, detection, prediction and analysis of positional features such as functional and other key sites, in protein sequences and the conserved patterns (motifs, profiles etc.) that may be used to describe them. Signal peptide cleavage sites