serpins similar to Drosophila melanogaster Serpin 42Da
This subfamily is composed mainly of insect serpins, including Drosophila melanogaster serpin 42Da. Serpins in insects function within development, wound healing and immunity. Serpin 42Da, previously serpin 4, is a serine protease inhibitor that is capable of remarkable functional diversity through the alternative splicing of four different reactive center loop exons. Insect serpins from stink bug, alfalfa leafcutting bee, red flour beetle, house fly, and brown planthopper are also included in this subfamily. 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.
Jiyao W et al.(2023). "The conserved domain database in 2023.",