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Insect Biochem Mol Biol. 2012 Sep;42(9):603-9. doi: 10.1016/j.ibmb.2012.04.007. Epub 2012 May 2.

Characterization of the hemoglobin of the backswimmer Anisops deanei (Hemiptera).

Author information

1
Institute of Zoology, University of Hamburg, Biocenter Grindel, Martin-Luther-King-Platz 3, D-20146 Hamburg, Germany.

Abstract

While O(2)-binding hemoglobin-like proteins are present in many insects, prominent amounts of hemoglobin have only been found in a few species. Backswimmers of the genera Anisops and Buenoa (Notonectidae) have high concentrations of hemoglobin in the large tracheal cells of the abdomen. Oxygen from the hemoglobin is delivered to a gas bubble and controls the buoyant density, which enables the bugs to maintain their position without swimming and to remain stationary in the mid-water zone where they hunt for prey. We have obtained the cDNA sequences of three Anisops deanei hemoglobin chains by RT-PCR and RACE techniques. The deduced amino acid sequences show an unusual insertion of a single amino acid in the conserved helix E, but this does not affect protein stability or ligand binding kinetics. Recombinant A. deanei hemoglobin has an oxygen affinity of P(50) = 2.4 kPa (18 torr) and reveals the presence of a dimeric fraction or two different conformations. The absorption spectra demonstrate that the Anisops hemoglobin is a typical pentacoordinate globin. Phylogenetic analyses show that the backswimmer hemoglobins evolved within Heteroptera and most likely originated from an intracellular hemoglobin with divergent function.

PMID:
22575160
DOI:
10.1016/j.ibmb.2012.04.007
[Indexed for MEDLINE]

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