Isolation and cDNA cloning of a novel red colour-related pigment-binding protein derived from the shell of the shrimp, Litopenaeus vannamei

- A 75 kDa red colour-related protein (LvPBP75) was purified from the shell of Litopenaeus vannamei.
- LvPBP75 was identified as hemocyanin by MALDI-TOF-MS and cDNA cloning.
- LvPBP75 cDNA contains a 1986 bp ORF, that encodes a protein of 662 amino acids.
- Novel function of hemocyanin as binding with pigment, and correlated with shrimp shell colour change.

Pigment-binding proteins play important roles in crustacean shell colour change. In this study, a red colour-related pigment-binding protein, designated LvPBP75, was purified from the shell of Litopenaeus vannamei. HPLC and PAGE analysis showed that LvPBP75 was a homogeneous monomer with molecular mass of 75 kDa. Peptide mass fingerprint analysis revealed that LvPBP75 belonged to hemocyanin, and the released pigment from heated LvPBP75 showed a λmax at 481 nm in acetone. The significant red-colour change temperatures were detected at 30 and 80 °C, respectively. Based on the determined amino acid fragments, a full-length cDNA of LvPBP75 was cloned and sequenced. The ORF encodes a protein of 662 amino acids having 80% identity with penaeidae hemocyanin. These results strongly suggest a novel function of hemocyanin, namely binding with pigment, and its involvement in L. vannamei shell colour change.