Signal peptide cleavage site, prediction

Figure 12.15. Prediction of signal peptide cleavage site. The profile plot shows the prediction of signal peptide cleavage site of duck lysozyme by SignalP.

Nielsen, H., Engelbrecht, J., Brunak, S., and von Heijne, G. (1997). Identification of prokaryotic and eukaryotic signal peptides and prediction of their cleavage sites. Protein Eng. 10, 1-6. 

G. (1997) Identification of prokaryotic and eukaryotic signal peptides and prediction of their cleavage sites, Protein Engineering 10 1-6. 

Nielsen, H., J. Engelbrecht, S. Brunak, and G. von Heijne. 1997. A neural network method for identification of prokaryotic and eukaroytoic signal peptides and prediction of their cleavage sites. Internationl Journal of Neural Systems 8 581-99. 

The signal sequence is proteoly tically cleaved by signal pepetidase (member enzyme of translocon) once protein is translocated. The eukaryotic signal peptidases have multiple catalytic subunits with broad substrate specificity. The enzyme generally cleaves at a site that has small aliphatic residues at position -1 and -3. On-line prediction of signal peptide and cleavage site is available at PrediSi (http //www.predisi.de). 

Figure 5. Comparison of the leader sequences of human prothrombin (73-75), factor VII (97), factor IX (98-100), factor X (102-106), protein C (108-109) and protein S (96) as predicted from the cDNA sequences. Identical residues in corresponding positions in two or more of the protein sequences are boxed. The sequences are numbered backwards from the cleavage site that gives rise to the mature plasma form of the proteins. The position of a 22 amino acid insertion in the leader peptide of factor VII which gives rise to the alternate 60 amino acid leader sequence (136) is denoted by the solid triangle. The sites of signal peptidase cleavage in factor IX (125,126) and in protein C (81) are indicated by the vertical arrows.

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