Carotenoprotein crustacyanin

UNRAVELLING THE CHEMICAL BASIS OF THE BATHOCHROMIC SHIFT OF THE LOBSTER CARAPACE CAROTENOPROTEIN CRUSTACYANIN... 

P. F. Zagalsky, E. E. Eliopoulos, and J. B. Findlay, The lobster carapace carotenoprotein, alpha-crustacyanin. A possible role for tryptophan in the bathchromic spectral shift of protein-bound astaxanthin, J. Biochem. 274 (1991) 79-83. 

Infrared and Resonance Raman Spectroscopy. Reviewson the uses of resonance Raman spectroscopy in biochemistry and biology include sections on carotenoproteins, visual pigments, and bacteriorhodopsin. The resonance Raman spectrum of the lowest excited triplet state of /3-carotene has been reported.A resonance Raman method has been used for the quantitative analysis of /3-carotene and lutein (20) in tobacco.The mechanism of carotenoid-protein interactions in the carotenoproteins ovoverdin and /3-crustacyanin has been investigated by resonance Raman spectroscopy. " 2 axanthin (24) has been used as a resonance Raman probe of membrane structure. " The resonance Raman spectra have been reported of all-frans-anhydrovitamin A (194), " /3-ionone, retinals, and Schiff bases.The technique has been used extensively to study... 

Conjugated keto-carotenoids are complexed stoichiometrically with a simple protein in true carotenoproteins. Such carotenoproteins are encountered particularly in external tissues in the carapace of Crustacea and the skin of Echinodermata. The blue crustacyanin from lobster carapace is the best studied carotenoprotein, as described in several reviews [8,81,82], Detailed isolations methods are given [83], Our group has been involved in early studies on crustacyanin [84], asteriarubin [85], alloporin [86] and linckia-cyanin [87]. 

Astaxanthin (17) is not covalently bound in carotenoproteins and may be extracted from crustacyanin, providing a colourless apoprotein. The blue colour may be reconstituted with a range of conjugated ketocarotenoids [88], All optical isomers (3i ,3 i 3S,3 S and the meso... 

Consequently, the current picture concerning the bathochromic shift in carotenoproteins, such a crustacyanin (9), involves partial positive charge caused by hydrogen bonding of the astaxanthin (17) keto groups, cf. the blue oxonium ions discussed above. 

Carotenoid-Protein Complexes. The partial characterization of an astaxanthin- or zeaxanthin-containing carotenoprotein (mol. wt. >30000) from hydrocorals has been reported. Other papers present a spectroscopic characterization of the lobster pigment a-crustacyanin and report effects of changes in pH and ionic strength on its spectroscopic properties. ... 

Milicua JCG, Garate AM, Barbon PG, Gomez R (1986) Relatedness between a-crustacyanin from the lobster Homarus americanus and the blue carotenoprotein from the crayfish Procambrus clarkii. Comp Biochem Physiol 85B 621-626... 

Lately the CD spectrum of the carotenoprotein a-crustacyanin which exhibits two maxima at 690 nm (-b) and 583 nm (—), in phosphate buffer has been interpreted in terms of dipole-dipole coupling between the transition moments of the two carotenoid molecules on each subunit. The CD splitting corresponded to an exciton band width of 2800 cm which leads to an interchromophore distance of ca. 13 A 123 a). 

Ketocarotenoids such as astaxanthin (28) and its acetylenic derivatives (34) and (80) occur in coloured carotenoprotein complexes examples of which are crustacyanin (52, 123), ovoverdin (48), ovorubin (50), allo-porin (151) and asteriarubin (65). It has been suggested that the carotenoids may function by stabilizing the tertiary structure of the proteins involved (51). Recombination experiments between the colourless apoproteins and selected carotenoids have demonstrated the need for conjugated 4,4 -keto groups for the formation of these complexes (151,180). However, detailed studies for instance with (3S,3 5)-astaxanthin (28), its 3R,3 R enantiomer and the mesoform for elucidation of the steric requirements for the complexing carotenoid have not yet been reported. 

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