Characterisation of cavortin, the major haemolymph protein of the Pacific oyster(Crassostrea gigas)

Abstract

Evidence suggests that members of the oyster genus Crassostrea share a common haemolymphprotein. Cavortin, the major haemolymph protein of the Pacific oyster (Crassostrea gigas), comprises 174 amino acid residues totalling 19.4 kDa and is rich in histidine and aspartic acid. The protein consists of a single Cu/Zn SOD (superoxide dismutase) derived domain showing homology to each of the three SOD-like domains of pernin, the related 60 kDa protein from the green-lipped mussel (Perna canaliculus). Despite some homology to Cu/Zn SOD sequences we found no compelling evidence that it has retained SOD function. Cavortin has affinity for several divalent cations, particularly iron. Each cavortin monomer is able to bind 8-11 iron ions, but can sequester considerably more iron, presumably by forming spheroid particles. The primary function of cavortin, like pernin, has been altered during the course of evolution, but has yet to be determined unambiguously. A likely role is as a metal ion chaperone.

Use of OmpU porins for attachment and invasion of Crassostrea gigas immune cells by the oyster pathogen Vibrio splendidus

“…S3). The aberrant migration of Cg-EcSOD variants at ∼30 kDa instead of 20 kDa is in agreement with previous studies (19,30). Fractions f6 and f7, which could contain different variants or foldamers of Cg-EcSOD, as presumed from their different chromatographic behavior (31), displayed similar binding to LGP32 (Fig.…”

Evidence that the major hemolymph protein of the Pacific oyster, Crassostrea gigas, has antiviral activity against herpesviruses

“…Anti-HSV-1 activity in each fraction was positively correlated to the abundance of cavortin in the sample (Table 1). Antiviral activity of cavortin was confirmed using a second approach of sedimenting cavortin by ultracentrifugation according to Scotti et al (2007) and assaying crude cavortin (F4b) and cavortin-free hemolymph (F3b) in the HSV-1 and Vero cell plaque reduction assay (Fig. 5).…”

“…Cavortin was pelleted from oyster hemolymph by ultracentrifugation (286,000Âg for 3 h in a Beckman NTV90 rotor) according to Scotti et al (2007) and the pellet resuspended in 0.2 lm filtered seawater. Purity of cavortin was assessed using SDS-PAGE in 14% acrylamide/bis gel and antiviral activity confirmed by assaying whole hemolymph, cell-free hemolymph (1000Âg for 5 min), cavortin-free hemolymph (286,000Âg for 3 h) and purified cavortin using the HSV-1 and Vero cell plaque reduction assay described above.…”

Marine Snails and Slugs: a Great Place To Look for Antiviral Drugs

“…This protein has amino acid sequence similarity to the major hemolymph protein of the eastern oyster C. virginica, which is considered to have a domain resembling superoxide dismutase, which has been shown to have antiviral properties (59)(60)(61)(62), but the protein reportedly lacks superoxide dismutase activity (63)(64)(65). The mechanism for antiviral activity of cavortin remains unclear.…”