Part:BBa_K2760001:Design

DsbAss (E. coli signal peptide)

This gene codes for the signal peptide DsbAss from the E. coli SRP pathway. The E. coli Sec secretion pathway can also utilize a co-translational mechanism of export that couples translation of proteins by the ribosome with secretion through the SecYEG channel [the signal peptide recognition particle (SRP) pathway]. The SRP pathway relies on the SRP particle, which recognizes an N-terminal signal peptide with highly hydrophobic core during protein secretion and the binding affinity of the SRP particle for signal peptides increases with the hydrophobicity of the h-region of signal peptides [1].

Signal peptides are short peptides (20–30 amino acid residues) that have three structural domains; an amino-terminal region with a net positive charge (the n-region), then an hydrophobic region (the h-region) and a protease recognition sequence (the c-region) with a preference for small residues at the −3 (P3) and −1 (P1) positions relative to the cleavage site [1]. Studies show that the hydrophobic region in the signal peptide plays an important role for protein translocation across the bacterial cytoplasmic membrane due to the interaction of the h-region with the membrane during protein translocation. Several studies have also reported that translocation efficiency increases with the length and hydrophobicity of the h-region, and a minimum hydrophobicity is required for their secretion function [1].

References: [1] Han, S., Machhi, S., Berge, M., Xi, G., Linke, T., & Schoner, R. (2017). Novel signal peptides improve the secretion of recombinant Staphylococcus aureus Alpha toxinH35L in Escherichia coli. AMB Express, 7, 93. http://doi.org/10.1186/s13568-017-0394-1