Structural characterization of recombinant crustacyanin subunits from the lobsterHomarus americanus

Abstract

Crustacean crustacyanin proteins are linked to the production and modification of carapace colour, with direct implications for fitness and survival. Here, the structural and functional properties of the two recombinant crustacyanin subunits H(1) and H(2) from the American lobster Homarus americanus are reported. The two subunits are structurally highly similar to the corresponding natural apo crustacyanin CRTC and CRTA subunits from the European lobster H. gammarus. Reconstitution studies of the recombinant crustacyanin proteins H(1) and H(2) with astaxanthin reproduced the bathochromic shift of 85-95 nm typical of the natural crustacyanin subunits from H. gammarus in complex with astaxanthin. Moreover, correlations between the presence of crustacyanin genes in crustacean species and the resulting carapace colours with the spectral properties of the subunits in complex with astaxanthin confirmed this genotype-phenotype linkage.

Functional and structural properties of red color‐related pigment‐binding protein from the shell of Litopenaeus vannamei

“…The binding ratio of rLvPBP75 and ATX was calculated to be 0.346 based on their molar mass, which means that 1 mol L −1 ATX could bind with 26 kDa protein. This is in accordance with previous studies on crustacyanin subunits, where about 1 mol L −1 ATX was combined with 22 kDa protein . Therefore the protein was expected to dominate the CD spectrum of the pigment‐binding complex.…”

“…Studies on pigment‐binding proteins derived from lobster shell revealed that the pigment was found in a pigment‐binding pocket mainly formed by hydrophobic amino acids . It was linked to the amino acids by some short hydrogen bonds .…”

“…Studies on pigment‐binding proteins derived from lobster shell revealed that the pigment was found in a pigment‐binding pocket mainly formed by hydrophobic amino acids . It was linked to the amino acids by some short hydrogen bonds . Thermal denaturation of proteins has been demonstrated to be associated with the increased breakage of hydrogen bonds and hydrophobic interactions .…”

“…Alcohol denatures protein by disrupting the hydrogen bonds inside the protein and forming new hydrogen bonds between alcohol molecules and protein side chains . The hydrogen bond formed between hydrophobic amino acid and pigment was the main chemical bond maintaining the stability of the pigment‐binding pocket . Once it was disrupted by alcohol molecules, the color change could be detected due to the release of pigment from the pigment‐binding pocket.…”

Carotenoids in Aquatic Ecosystems and Aquaculture: A Colorful Business with Implications for Human Health

“…In the exoskeleton of crustaceans, astaxanthin exists as carotenoproteins such as crustacyanin, and exhibits purple, blue to blue-black (e.g., lobster Homarus gammarus), and yellow colors. These colors have direct implications for the fitness and survival of many crustaceans via camouflage or mate selection (Wade et al, 2009;Ferrari et al, 2012).…”