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Diversity and evolution of coral fluorescent proteins.

Alieva NO, Konzen KA, Field SF, Meleshkevitch EA, Hunt ME, Beltran-Ramirez V, Miller DJ, Wiedenmann J, Salih A, Matz MV - PLoS ONE (2008)

Bottom Line: Both proteins were green such as found elsewhere outside class Anthozoa.Interestingly, a substantial fraction of the all-coral ancestral protein had a chromohore apparently locked in a non-fluorescent neutral state, which may reflect the transitional stage that enabled rapid color diversification early in the history of coral FPs.Our results highlight the extent of convergent or parallel evolution of the color diversity in corals, provide the foundation for experimental studies of evolutionary processes that led to color diversification, and enable a comparative analysis of structural determinants of different colors.

View Article: PubMed Central - PubMed

Affiliation: Section of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America.

ABSTRACT
GFP-like fluorescent proteins (FPs) are the key color determinants in reef-building corals (class Anthozoa, order Scleractinia) and are of considerable interest as potential genetically encoded fluorescent labels. Here we report 40 additional members of the GFP family from corals. There are three major paralogous lineages of coral FPs. One of them is retained in all sampled coral families and is responsible for the non-fluorescent purple-blue color, while each of the other two evolved a full complement of typical coral fluorescent colors (cyan, green, and red) and underwent sorting between coral groups. Among the newly cloned proteins are a "chromo-red" color type from Echinopora forskaliana (family Faviidae) and pink chromoprotein from Stylophora pistillata (Pocilloporidae), both evolving independently from the rest of coral chromoproteins. There are several cyan FPs that possess a novel kind of excitation spectrum indicating a neutral chromophore ground state, for which the residue E167 is responsible (numeration according to GFP from A. victoria). The chromoprotein from Acropora millepora is an unusual blue instead of purple, which is due to two mutations: S64C and S183T. We applied a novel probabilistic sampling approach to recreate the common ancestor of all coral FPs as well as the more derived common ancestor of three main fluorescent colors of the Faviina suborder. Both proteins were green such as found elsewhere outside class Anthozoa. Interestingly, a substantial fraction of the all-coral ancestral protein had a chromohore apparently locked in a non-fluorescent neutral state, which may reflect the transitional stage that enabled rapid color diversification early in the history of coral FPs. Our results highlight the extent of convergent or parallel evolution of the color diversity in corals, provide the foundation for experimental studies of evolutionary processes that led to color diversification, and enable a comparative analysis of structural determinants of different colors.

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Positions of emission maxima in the mutated purple chromoprotein gfasCP in comparison to the blue amilCP.Horizontal axis is wavelength in nanometers, the bars indicate the position of the absorption peak in the mutant. The colors of the bars approximately correspond to the colors of the mutants. Mutations S64C and S183T were found to be responsible for the blue color in amilCP (numeration according to GFP). Mutation I162L results in a very slowly maturing protein, hence pale color of the corresponding bar. This effect is rescued by any of the other two mutations.
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pone-0002680-g004: Positions of emission maxima in the mutated purple chromoprotein gfasCP in comparison to the blue amilCP.Horizontal axis is wavelength in nanometers, the bars indicate the position of the absorption peak in the mutant. The colors of the bars approximately correspond to the colors of the mutants. Mutations S64C and S183T were found to be responsible for the blue color in amilCP (numeration according to GFP). Mutation I162L results in a very slowly maturing protein, hence pale color of the corresponding bar. This effect is rescued by any of the other two mutations.

Mentions: The chromoprotein amilCP is very similar to other coral chromoproteins in sequence; however, its absorption maximum (592 nm) is red-shifted by about 10 nm, making the protein appear blue instead of purple to the naked human eye. The closest homolog of amilCP is gfasCP, in comparison to which the amilCP protein has only four amino acid substitutions: S64C, I162L, S183T and S229P (numeration according to GFP from A. victoria). We investigated the effect of all combinations of these four mutations by introducing them into gfasCP and found that the blue phenotype was due to the substitutions at two sites: S64C and S183T (Fig. 4). The mutation at the fourth site (I162L) when introduced alone severely impaired the protein maturation: it took several days for soluble protein extract isolated after overnight induction of the expression in bacteria to develop color to the intensity comparable to what was seen already overnight in other variants. This effect was completely rescued by either of the two color-affecting mutations.


Diversity and evolution of coral fluorescent proteins.

Alieva NO, Konzen KA, Field SF, Meleshkevitch EA, Hunt ME, Beltran-Ramirez V, Miller DJ, Wiedenmann J, Salih A, Matz MV - PLoS ONE (2008)

Positions of emission maxima in the mutated purple chromoprotein gfasCP in comparison to the blue amilCP.Horizontal axis is wavelength in nanometers, the bars indicate the position of the absorption peak in the mutant. The colors of the bars approximately correspond to the colors of the mutants. Mutations S64C and S183T were found to be responsible for the blue color in amilCP (numeration according to GFP). Mutation I162L results in a very slowly maturing protein, hence pale color of the corresponding bar. This effect is rescued by any of the other two mutations.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2481297&req=5

pone-0002680-g004: Positions of emission maxima in the mutated purple chromoprotein gfasCP in comparison to the blue amilCP.Horizontal axis is wavelength in nanometers, the bars indicate the position of the absorption peak in the mutant. The colors of the bars approximately correspond to the colors of the mutants. Mutations S64C and S183T were found to be responsible for the blue color in amilCP (numeration according to GFP). Mutation I162L results in a very slowly maturing protein, hence pale color of the corresponding bar. This effect is rescued by any of the other two mutations.
Mentions: The chromoprotein amilCP is very similar to other coral chromoproteins in sequence; however, its absorption maximum (592 nm) is red-shifted by about 10 nm, making the protein appear blue instead of purple to the naked human eye. The closest homolog of amilCP is gfasCP, in comparison to which the amilCP protein has only four amino acid substitutions: S64C, I162L, S183T and S229P (numeration according to GFP from A. victoria). We investigated the effect of all combinations of these four mutations by introducing them into gfasCP and found that the blue phenotype was due to the substitutions at two sites: S64C and S183T (Fig. 4). The mutation at the fourth site (I162L) when introduced alone severely impaired the protein maturation: it took several days for soluble protein extract isolated after overnight induction of the expression in bacteria to develop color to the intensity comparable to what was seen already overnight in other variants. This effect was completely rescued by either of the two color-affecting mutations.

Bottom Line: Both proteins were green such as found elsewhere outside class Anthozoa.Interestingly, a substantial fraction of the all-coral ancestral protein had a chromohore apparently locked in a non-fluorescent neutral state, which may reflect the transitional stage that enabled rapid color diversification early in the history of coral FPs.Our results highlight the extent of convergent or parallel evolution of the color diversity in corals, provide the foundation for experimental studies of evolutionary processes that led to color diversification, and enable a comparative analysis of structural determinants of different colors.

View Article: PubMed Central - PubMed

Affiliation: Section of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America.

ABSTRACT
GFP-like fluorescent proteins (FPs) are the key color determinants in reef-building corals (class Anthozoa, order Scleractinia) and are of considerable interest as potential genetically encoded fluorescent labels. Here we report 40 additional members of the GFP family from corals. There are three major paralogous lineages of coral FPs. One of them is retained in all sampled coral families and is responsible for the non-fluorescent purple-blue color, while each of the other two evolved a full complement of typical coral fluorescent colors (cyan, green, and red) and underwent sorting between coral groups. Among the newly cloned proteins are a "chromo-red" color type from Echinopora forskaliana (family Faviidae) and pink chromoprotein from Stylophora pistillata (Pocilloporidae), both evolving independently from the rest of coral chromoproteins. There are several cyan FPs that possess a novel kind of excitation spectrum indicating a neutral chromophore ground state, for which the residue E167 is responsible (numeration according to GFP from A. victoria). The chromoprotein from Acropora millepora is an unusual blue instead of purple, which is due to two mutations: S64C and S183T. We applied a novel probabilistic sampling approach to recreate the common ancestor of all coral FPs as well as the more derived common ancestor of three main fluorescent colors of the Faviina suborder. Both proteins were green such as found elsewhere outside class Anthozoa. Interestingly, a substantial fraction of the all-coral ancestral protein had a chromohore apparently locked in a non-fluorescent neutral state, which may reflect the transitional stage that enabled rapid color diversification early in the history of coral FPs. Our results highlight the extent of convergent or parallel evolution of the color diversity in corals, provide the foundation for experimental studies of evolutionary processes that led to color diversification, and enable a comparative analysis of structural determinants of different colors.

Show MeSH
Related in: MedlinePlus