PPIB
Description
The PPIB (peptidylprolyl isomerase B) is a protein-coding gene located on chromosome 15.
Peptidyl-prolyl cis-trans isomerase B is an enzyme encoded by the PPIB gene. As a member of the peptidyl-prolyl cis-trans isomerase (PPIase) family, it catalyzes the cis-trans isomerization of proline imidic peptide bonds, crucial for regulating type I collagen folding. PPIases are highly conserved, found in most bacteria and eukaryotes. PPIB has a β-barrel structure with a hydrophobic core, consisting of eight anti-parallel β-strands capped by α-helices. The β-turns and loops within the strands provide flexibility to the barrel. PPIB is a 21 kDa protein with a C-terminal ER retention motif that targets it to the ER organelle, while its N-terminal extension binds to substrates. PPIB, like other PPIases, catalyzes the cis-trans isomerization of proline imidic peptide bonds, playing a role in protein folding and maturation. Proline is the only amino acid existing in both cis and trans conformations in vivo, and its isomerization is often the rate-limiting step in protein refolding.
PPIB is also known as CYP-S1, CYPB, HEL-S-39, OI9, SCYLP.
