serpin family A member 10, protein Z-dependent protease inhibitor
Protein Z-dependent protease inhibitor (ZPI) is a member of the serpin superfamily of proteinase inhibitors (clade A10). ZPI inhibits coagulation factor Xa, dependent on protein Z (PZ), a vitamin K-dependent plasma protein. ZPI also inhibits factor XIa in a process that does not require PZ. In general, SERine Proteinase INhibitors (serpins) exhibit conformational polymorphism shifting from native to cleaved, latent, delta, or polymorphic forms. Many serpins, such as antitrypsin and antichymotrypsin, function as serine protease inhibitors which regulate blood coagulation cascades. Non-inhibitory serpins perform many diverse functions such as chaperoning proteins or transporting hormones. Serpins are of medical interest because mutants have been associated with blood clotting disorders, emphysema, cirrhosis, and dementia. A classification based on evolutionary relatedness has resulted in the assignment of serpins to 16 clades designated A-P along with some orphans.
Comment:depending on the conformational state, the RC loop is surface accessible in the active form or buried and inserted as the central beta strand in the inactive form.
Structure:3H5C_A: Human ZPI RCL in an open, surface-accessible conformation
Jiyao W et al.(2023). "The conserved domain database in 2023.",