Description
Joining chain is an essential protein in mucosal immunity in many organisms including mammals. However, little is known about J chain in elasmobranchs such as nurse sharks. Their amino acid sequence appears to be missing key cysteines which could lead to structural differences when compared to mammalian J chain. This research aims to map the disulfide bond pattern in nurse shark J chain and to assess the similarities or differences between it and mammalian J chain. After isolating Immunoglobulin M (IgM) from whole nurse shark sera, the antibody was digested using the enzyme trypsin. The resulting peptides were separated using a HPLC/Mass spectrometer, and the subsequent data was analyzed using the MassMatrix disulfide bond mapping software. Bovine IgM was used as a control due to its known disulfide bonding pattern. Analysis using the disulfide bond mapping software resulted in some incorrectly mapped cysteines in the bovine J chain. Alternative enzymes for IgM digestion and a reagent with which to block the free cysteines that potentially cause bond scrambling are needed to optimize disulfide bond detection and are being investigated. Determining the disulfide bond pattern of nurse shark J chain can enlighten the potential function of the protein in the nurse sharks. As the nurse shark J chain is missing two key cysteines present in mammalian J chains, it may not have the same function as its mammalian counterparts. This potential difference in function suggests that the role of J chain in mucosal immunity may have evolved over time.
Mapping the Disulfide Bonds of Nurse Shark Joining Chain
Joining chain is an essential protein in mucosal immunity in many organisms including mammals. However, little is known about J chain in elasmobranchs such as nurse sharks. Their amino acid sequence appears to be missing key cysteines which could lead to structural differences when compared to mammalian J chain. This research aims to map the disulfide bond pattern in nurse shark J chain and to assess the similarities or differences between it and mammalian J chain. After isolating Immunoglobulin M (IgM) from whole nurse shark sera, the antibody was digested using the enzyme trypsin. The resulting peptides were separated using a HPLC/Mass spectrometer, and the subsequent data was analyzed using the MassMatrix disulfide bond mapping software. Bovine IgM was used as a control due to its known disulfide bonding pattern. Analysis using the disulfide bond mapping software resulted in some incorrectly mapped cysteines in the bovine J chain. Alternative enzymes for IgM digestion and a reagent with which to block the free cysteines that potentially cause bond scrambling are needed to optimize disulfide bond detection and are being investigated. Determining the disulfide bond pattern of nurse shark J chain can enlighten the potential function of the protein in the nurse sharks. As the nurse shark J chain is missing two key cysteines present in mammalian J chains, it may not have the same function as its mammalian counterparts. This potential difference in function suggests that the role of J chain in mucosal immunity may have evolved over time.