Comparative structural and functional studies of Sturgeon Hemoglobin (Acipenser persicus and Acipenser stellatus)

Document Type : Physiology (Animal)

Authors

1 Department of Marine Biology, Faculty of Marine Science and Technology, Islamic Azad University, Science and Research Branch, Tehran, Iran

2 Department of Biology, Pardis of Science, Tehran, P.O.Box: 14155-6455, Tehran, Iran

Abstract

Hemoglobin (Hb) variability is a commonly used index of phylogenetic differentiation and molecular adaptation in fish enabling them to adapt to different ecological conditions. In this study,  the  characteristics  of  Hbs  from  two  Sturgeon  species  of  the  Southern  Caspian  Sea Basin were investigated. After extraction and separation of hemoglobin from whole blood, the polyacrylamide  gel  electrophoresis  (SDS-PAGE),  cellulose  acetate  electrophoresis,  and isoelectric  focusing  (IEF)  were  used  to  confirm  Hb  variabilities  in  these  fishes.  We  showed that although both species have variable Hbs with different isoelectric points, their dominant Hbs  can  be  identified.  Ion  exchange  on  CM-cellulose  chromatography  was  used  for purification  of  the  dominant  Hbs  from  these  fishes.  The  accuracy  of  the  methods  was confirmed  by  IEF  and  SDSPAGE.  Spectral  studies  using  fluorescence  spectrophotometery indicated that although the Hbs from these fishes had similar properties. A comparative study of  Hbs  alpha-helix  secondary  substructures  was  performed  by  circular  dichroism spectropolarimetry  (CD)  analysis.  The  thermal  denaturation  properties  of  the  Hbs  were investigated by differential scanning calorimetry (DSC) .UV–vis spectrophotometery was also utilized to  measure  oxygen  affinity  of  Hbs  by  sodium  dithionite.    Oxygen  affinities  of  these Hbs  were  compared  using  Hb–oxygen  dissociation  curves.  Together,  these  results demonstrate  a  significant  relationship  between  oxygen  affinity,  hydrophobicity, themostability  and  alpha-helix  secondary  substructures  of  fish  hemoglobins  and environmental partial pressure of oxygen. 

Keywords

Journal of Animal Environment
Volume 5, Issue 2
September 2012
Pages 121-133

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