Verified Type I Signal Peptide Cleavages


A subset of the Verified Set mature protein starts confirm the cleavage sites for signal peptidase I and infer a periplasmic, outer membrane or extracellular protein localization. E. coli K-12 Verified type I signal peptides range in length from 17 to 52 amino acids. These proteins are linked to this subTopicPage.


In a few cases the N-terminal amino acid of the precursor protein has also been determined, but verifying the type I signal peptide cleavage site is not a direct verification of the translation start site. However, in most cases there is only one possible start site that allows for a good signal peptide prediction.

Asr has a verified 21 aa type I signal peptide and is located in the periplasm; an additional 37 aa are processed off the N-terminus by an unknown protease to activate Asr; the asr translation start codon was confirmed by site-directed mutagenesis (Seputiene, 2003). Asr is included in this SubTopic because it is located in the periplasm.

GltB is included in this SubTopic because the first 12 aa are cleaved and it is the cleavage site that is Verified; the GltB start site is predicted.