Adaptation of Proteins to the Cold in Antarctic Fish: A Role for Methionine? ...

• Main Authors: Berthelot, Camille, Clarke, Jane, Desvignes, Thomas, William Detrich, H, Flicek, Paul, Peck, Lloyd S, Peters, Michael, Postlethwait, John H, Clark, Melody S
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2019
• Subjects: Acclimatization; Animals; Antarctic Regions; Evolution, Molecular; Fish Proteins; Freezing; Methionine; Perciformes; Protein Folding; Transcriptome; Antarctic; Southern Ocean; Antarc*
• Online Access: https://dx.doi.org/10.17863/cam.36686; https://www.repository.cam.ac.uk/handle/1810/289437

The evolution of antifreeze glycoproteins has enabled notothenioid fish to flourish in the freezing waters of the Southern Ocean. Whereas successful at the biodiversity level to life in the cold, paradoxically at the cellular level these stenothermal animals have problems producing, folding, and degrading proteins at their ambient temperatures of -1.86 °C. In this first multi-species transcriptome comparison of the amino acid composition of notothenioid proteins with temperate teleost proteins, we show that, unlike psychrophilic bacteria, Antarctic fish provide little evidence for the mass alteration of protein amino acid composition to enhance protein folding and reduce protein denaturation in the cold. The exception was the significant overrepresentation of positions where leucine in temperate fish proteins was replaced by methionine in the notothenioid orthologues. We hypothesize that these extra methionines have been preferentially assimilated into the genome to act as redox sensors in the highly ...