Structural and functional studies of hemoproteins from polar marine organisms

• Main Author: Coppola, Daniela
• Format: Doctoral or Postdoctoral Thesis
• Language: Italian; English
• Published: 2011
• Subjects: Antarctic; Antarc*; Antarctica
• Online Access: http://www.fedoa.unina.it/8864/; http://www.fedoa.unina.it/8864/1/Daniela_Coppola.pdf; https://doi.org/10.6092/UNINA/FEDOA/8864

Antarctica, more than any other habitat on Earth, represents a unique natural laboratory for fundamental research on the processes that have produced biological diversity in extreme environments and, at the same time, offers potential biotechnological opportunities. One of the most interesting models, within vertebrates, to study the biological responses to cold is provided by Notothenioidei, a group of related species constituting the dominant suborder of teleosts living in Antarctica. To preserve biological activity, five high-Antarctic families of this suborder, living in a stable, extremely cold, and well-oxygenated marine environment, have evolved unique specialisations, including modification of hematological features, having reduced hemoglobin concentration and multiplicity. On the contrary, the three remaining small basal sub-Antarctic families exhibit high hemoglobin multiplicity, probably as a response to temperature differences and fluctuations of temperate waters, and provide an excellent opportunity for understanding the processes involved in cold adaptation. In this thesis the structure and function of the oxygen-transport system of two sub-Antarctic notothenioids, Eleginops maclovinus (family Eleginopidae) and Dissostichus eleginoides (family Nototheniidae), were described and compared with respect to high-Antarctic species, and in particular to the hemoglobin of Trematomus bernacchii (family Nototheniidae). In contrast to high-Antarctic notothenioids, the hemoglobins of E. maclovinus and D. eleginoides show high oxygen affinity and cooperativity, and marked Root effect. In addition, in the major component of E. maclovinus, a strong stabilization of the low affinity T quaternary state and some peculiar features at the level of the tertiary and quaternary structures have been identified. The study of these fish and their adaptations is also interesting in the production of new treatments for blood-related diseases and syndromes, including anaemia, hemoglobinopathies and thalassemias or in the ...