FkpA
FkpA is a periplasmic folding catalyst found in many Gram-negative bacteria, most notably Escherichia coli. It is directed to the periplasm by a Sec-dependent signal peptide and typically functions as a homodimer in this compartment. In the periplasm, FkpA contributes to proper protein folding under normal and stress conditions, assisting the maturation of envelope and secreted proteins.
Structurally, FkpA comprises two functional domains: an N-terminal dimerization domain and a C-terminal FKBP-like peptidyl-prolyl cis-trans
In vivo, FkpA supports the correct folding of a range of periplasmic and outer membrane proteins, including
In research contexts, FkpA serves as a model of a dual-function chaperone–PPIase and is used to study