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Hemoglobin structure/function and globin-gene evolution in the Arctic fish Liparis tunicatus
Daniela Giordano1, Alessandro Vergara, H Caroline Lee
1Institute of Protein Biochemistry, CNR, Via Pietro Castellino 111, I-80131 Naples, Italy.
Gene
|July 10, 2007
Summary
Arctic fish hemoglobin adaptations are crucial for understanding marine evolution. This study characterizes hemoglobin from Liparis tunicatus, revealing unique structural and functional traits linked to polar environments and evolutionary history.
Area of Science:
- Marine biology
- Molecular evolution
- Fish physiology
Background:
- Arctic fish exhibit diverse hemoglobin (Hb) multiplicity, contrasting with Antarctic Notothenioidei.
- Liparis tunicatus, an Arctic fish, possesses a major Hb 1 and a minor Hb 2.
- Understanding molecular adaptations in Arctic marine organisms is vital.
Purpose of the Study:
- To structurally and functionally characterize hemoglobin 1 (Hb 1) from the Arctic fish Liparis tunicatus.
- To investigate the evolutionary relationships of polar fish globins.
Main Methods:
- Structural and functional characterization of L. tunicatus Hb 1.
- Amino-acid sequencing of beta-globin chain.
- Electron paramagnetic resonance (EPR) spectroscopy.
- Phylogenetic analysis of globin sequences.
Main Results:
- L. tunicatus Hb 1 exhibits low oxygen affinity with significant Bohr and Root effects.
- Unusual amino-acid substitutions were identified in the beta chain at the phosphate-binding site and position E11.
- EPR spectra indicated the formation of a ferric penta-coordinated species at physiological pH.
- Phylogenetic analysis suggests close evolutionary relationships between Cottoidei and Notothenioidei globins.
Conclusions:
- The unique Hb characteristics of L. tunicatus are likely adaptations to the Arctic environment.
- Globin sequence evolution in polar fish appears influenced by phylogenetic proximity and lifestyle.
- This study provides insights into the molecular basis of adaptation in polar marine organisms.
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