RiAFP refers to an antifreeze protein (AFP) produced by the Rhagium inquisitor longhorned beetle. It is a type V antifreeze protein with a molecular weight of 12.8 kDa; this type of AFP is noted for its hyperactivity.[1][2][3]R. inquisitor is a freeze-avoidant species, meaning that, due to its AFP, R. inquisitor prevents its body fluids from freezing altogether.[3] This contrasts with freeze-tolerant species, whose AFPs simply depress levels of ice crystal formation in low temperatures. Whereas most insect antifreeze proteins contain cysteines at least every sixth residue, as well as varying numbers of 12- or 13-mer repeats of 8.3-12.5kDa,[4] RiAFP is notable for containing only one disulfide bridge. This property of RiAFP makes it particularly attractive for recombinant expression and biotechnological applications.
^Kristiansen E, Ramløv H, Højrup P, Pedersen SA, Hagen L, Zachariassen KE (February 2011). "Structural characteristics of a novel antifreeze protein from the longhorn beetle Rhagium inquisitor". Insect Biochem Molec. 41 (2): 109–117. Bibcode:2011IBMB...41..109K. doi:10.1016/j.ibmb.2010.11.002. PMID21078390.
^ abKristiansen E, Ramløv H, Hagen L, Pedersen SA, Andersen RA, Zachariassen KE (September 2005). "Isolation and characterization of hemolymph antifreeze proteins from larvae of the longhorn beetle Rhagium inquisitor". Comp Biochem Physiol B. 142 (1): 90–97. doi:10.1016/j.cbpc.2005.06.004. PMID15993638.