Molecular structure and functional adaptations of hemoglobins from Antarctic marine organisms

This research dealing with fish, bird and mammal hemoglobins is in the fram ework of the study of the molecular basis of cold adaptation in Antarctic o rganisms. The study of hemoglobin structural and functional properties in A ntarctic teleosts allowed a correlation of amino acid sequence, multiplicit y, and oxygen-binding features with ecological constraints. Amino acid sequ ences of alpha and beta chains were analysed to build phylogenetic trees, w hile thc organisation and expression of globin genes was studied. The respi ratory proteins of Antarctic birds were investigated, in relation with the oxygen demands arising from their characteristic behaviour (diving or Right ) and, in general, from thr extreme conditions of the Antarctic habitat. Th e study of Weddell seal hemoglobins indicated that the combined effect of c arbon dioxide, organic phosphates and temperature optimises oxygen delivery to all tissues in spite of their relative heterothermia. The crystallograp hic structure of the carbonmonoxy derivative of Trematomus newnesi major he moglobin was resolved, giving new insight into the study of the Root effect . The molecular models of skua hemoglobins revealed the presence of a secun d, additional phosphate binding site located between the two alpha chains, paving the way to further studies.