Cloning, expression, and activity of type IV antifreeze protein from cultured subtropical olive flounder (Paralichthys olivaceus)
Abstract Antifreeze proteins (AFPs) lower the freezing point but not the melting point of aqueous solutions by inhibiting the growth of ice crystals via an adsorption-inhibition mechanism. However, the function of type IV AFP (AFP IV) is questionable, as its antifreeze activity is on the verge of de...
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| Format: | Article |
| Language: | English |
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The Korean Society of Fisheries and Aquatic Science
2016-10-01
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| Series: | Fisheries and Aquatic Sciences |
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| Online Access: | http://link.springer.com/article/10.1186/s41240-016-0033-9 |
| _version_ | 1818560265901309952 |
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| author | Jong Kyu Lee Hak Jun Kim |
| author_facet | Jong Kyu Lee Hak Jun Kim |
| author_sort | Jong Kyu Lee |
| collection | DOAJ |
| description | Abstract Antifreeze proteins (AFPs) lower the freezing point but not the melting point of aqueous solutions by inhibiting the growth of ice crystals via an adsorption-inhibition mechanism. However, the function of type IV AFP (AFP IV) is questionable, as its antifreeze activity is on the verge of detectable limits, its physiological concentration in adult fish blood is too low to function as a biological antifreeze, and its homologues are present even in fish from tropic oceans as well as freshwater. Therefore, we speculated that AFP IV may have gained antifreeze activity not by selective pressure but by chance. To test this hypothesis, we cloned, expressed, and assayed AFP IV from cultured subtropical olive flounder (Paralichthys olivaceus), which do not require antifreeze protein for survival. Among the identified expressed sequence tags of the flounder liver sample, a 5′-deleted complementary DNA (cDNA) sequence similar to the afp4 gene of the longhorn sculpin was identified, and its full-length cDNA and genome structure were examined. The deduced amino acid sequence of flounder AFP IV shared 55, 53, 52, and 49 % identity with those of Pleuragramma antarcticum, Myoxocephalus octodecemspinosus, Myoxocephalus scorpius, and Notothenia coriiceps, respectively. Furthermore, the genomic structure of this gene was conserved with those of other known AFP IVs. Notably, the recombinant AFP IV showed a weak but distinct thermal hysteresis of 0.07 ± 0.01 °C at the concentration of 0.5 mg/mL, and ice crystals in an AFP IV solution grew star-shaped, which are very similar to those obtained from other polar AFP IVs. Taken together, our results do not support the hypothesis of evolution of AFP IV by selective pressure, suggesting that the antifreeze activity of AFP IV may have been gained by chance. |
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| id | doaj.art-42b6a9ac23d54e3788b7166b0f455c8b |
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| language | English |
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| publishDate | 2016-10-01 |
| publisher | The Korean Society of Fisheries and Aquatic Science |
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| series | Fisheries and Aquatic Sciences |
| spelling | doaj.art-42b6a9ac23d54e3788b7166b0f455c8b2022-12-21T23:24:38ZengThe Korean Society of Fisheries and Aquatic ScienceFisheries and Aquatic Sciences2234-17572016-10-011911710.1186/s41240-016-0033-9Cloning, expression, and activity of type IV antifreeze protein from cultured subtropical olive flounder (Paralichthys olivaceus)Jong Kyu Lee0Hak Jun Kim1Department of Microbiology, College of Natural Sciences, Pukyong National UniversityDepartment of Chemistry, College of Natural Sciences, Pukyong National UniversityAbstract Antifreeze proteins (AFPs) lower the freezing point but not the melting point of aqueous solutions by inhibiting the growth of ice crystals via an adsorption-inhibition mechanism. However, the function of type IV AFP (AFP IV) is questionable, as its antifreeze activity is on the verge of detectable limits, its physiological concentration in adult fish blood is too low to function as a biological antifreeze, and its homologues are present even in fish from tropic oceans as well as freshwater. Therefore, we speculated that AFP IV may have gained antifreeze activity not by selective pressure but by chance. To test this hypothesis, we cloned, expressed, and assayed AFP IV from cultured subtropical olive flounder (Paralichthys olivaceus), which do not require antifreeze protein for survival. Among the identified expressed sequence tags of the flounder liver sample, a 5′-deleted complementary DNA (cDNA) sequence similar to the afp4 gene of the longhorn sculpin was identified, and its full-length cDNA and genome structure were examined. The deduced amino acid sequence of flounder AFP IV shared 55, 53, 52, and 49 % identity with those of Pleuragramma antarcticum, Myoxocephalus octodecemspinosus, Myoxocephalus scorpius, and Notothenia coriiceps, respectively. Furthermore, the genomic structure of this gene was conserved with those of other known AFP IVs. Notably, the recombinant AFP IV showed a weak but distinct thermal hysteresis of 0.07 ± 0.01 °C at the concentration of 0.5 mg/mL, and ice crystals in an AFP IV solution grew star-shaped, which are very similar to those obtained from other polar AFP IVs. Taken together, our results do not support the hypothesis of evolution of AFP IV by selective pressure, suggesting that the antifreeze activity of AFP IV may have been gained by chance.http://link.springer.com/article/10.1186/s41240-016-0033-9Paralichthys olivaceusSubtropical fishType IV antifreeze proteinThermal hysteresis |
| spellingShingle | Jong Kyu Lee Hak Jun Kim Cloning, expression, and activity of type IV antifreeze protein from cultured subtropical olive flounder (Paralichthys olivaceus) Fisheries and Aquatic Sciences Paralichthys olivaceus Subtropical fish Type IV antifreeze protein Thermal hysteresis |
| title | Cloning, expression, and activity of type IV antifreeze protein from cultured subtropical olive flounder (Paralichthys olivaceus) |
| title_full | Cloning, expression, and activity of type IV antifreeze protein from cultured subtropical olive flounder (Paralichthys olivaceus) |
| title_fullStr | Cloning, expression, and activity of type IV antifreeze protein from cultured subtropical olive flounder (Paralichthys olivaceus) |
| title_full_unstemmed | Cloning, expression, and activity of type IV antifreeze protein from cultured subtropical olive flounder (Paralichthys olivaceus) |
| title_short | Cloning, expression, and activity of type IV antifreeze protein from cultured subtropical olive flounder (Paralichthys olivaceus) |
| title_sort | cloning expression and activity of type iv antifreeze protein from cultured subtropical olive flounder paralichthys olivaceus |
| topic | Paralichthys olivaceus Subtropical fish Type IV antifreeze protein Thermal hysteresis |
| url | http://link.springer.com/article/10.1186/s41240-016-0033-9 |
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