A signal peptide , or signal sequence , is a short (from 3 to 60 amino acids ) amino acid sequence in a protein that provides cotranslational or post-translational transport of the protein to the corresponding organelle ( nucleus , mitochondria , endoplasmic reticulum , chloroplast , apoplast or peroxisome ). After delivery of the protein to the organelle, the signal peptide can be cleaved by the action of a specific signal protease .
Types of signal peptides
| Organella | Amino Acid Sequence |
|---|---|
| cell nucleus | -Pro-Pro-Lys-Lys-Lys-Arg-Lys-Val- |
| transportation to the endoplasmic reticulum | H 2 N-Met-Met-Ser-Phe-Val-Ser-Leu-Leu-Leu-Val-Gly-Ile-Leu-Phe-Trp-Ala-Thr-Glu-Ala-Glu-Gln-Leu-Thr- Lys-Cys-Glu-Val-Phe-Gln- |
| delay in the endoplasmic reticulum | -Pro-Pro-Lys-Lys-Lys-Arg-Lys-Val- |
| mitochondria (matrix) | H 2 N-Met-Leu-Ser-Leu-Arg-Gln-Ser-Ile-Arg-Phe-Phe-Lys-Pro-Ala-Thr-Arg-Thr-Leu-Cys-Ser-Ser-Arg-Tyr- Leu-Leu- |
| peroxisome (PTS1) | -Ser-Lys-Leu-COOH |
| peroxisome (PTS2) | H 2 N ----- Arg-Leu-X 5 -His-Leu- |
See also
Gunter Blobel
Links
- Signal (peptide) of protein sorting
- Macromolecule Transport
- SPdb (Signal Peptide Database)
- SignalP - prediction of the presence and localization of signal peptide cleavage sites in the amino acid sequences of various organisms.