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Extended Signal Peptide of Type V secretion system This conserved domain is called ESPR for Extended Signal Peptide Region. It is present at the N-terminus of the signal peptides of proteins belonging to the Type V secretion systems, including the autotransporters (T5aSS), TpsA exoproteins of the two-partner system (T5bSS) and trimeric autotransporters (TAAs). So far, the ESPR is present only in Gram-negative bacterial proteins originating from the classes Beta- and Gamma-proteobacteria. ESPR severely impairs inner membrane translocation, suggesting that it adopts a particular conformation or it interacts with a cytoplasmic or inner membrane co-factor, prior to exportation. Deletion of ESPR causes mis-folding of the TAAs passenger domain in the periplasm, substantially impairing its translocation across the outer membrane. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",