A Hemoglobin with an Optical Function*
- A. H. Jay Burr‡,
- Peter Hunt§,
- Donna R. Wagar‡,
- Sylvia Dewilde¶,
- Mark L. Blaxter§,
- Jacques R. Vanfleteren‖ and
- Luc Moens¶**
- From the ‡Department of Biological Sciences, Simon Fraser University, Vancouver, British Columbia V5A 1S6, Canada, the§Institute of Cell, Animal, and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, United Kingdom, the¶Department of Biochemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium, and the‖Department of Biology, University of Ghent, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium
Abstract
Hemoglobins are best known as oxygen transport proteins. Here we describe a hemoglobin from the parasitic nematodeMermis nigrescens (Mn-GLB-E) that has an optical, light shadowing function. The protein accumulates to high concentration as intracellular crystals in the ocellus of mature phototactic adult females while also being expressed at low concentration in other tissues. It differs in sequence and expression pattern from Mn-GLB-B, a second Mermis globin. It retains the structure and oxygen-binding and light-absorbing properties typical of nematode hemoglobins. As such, recruitment to a shadowing role in the eye appears to have occurred by changes in expression without modification of biochemistry. Both globins are coded by genes interrupted by two introns at the conserved positions B12.2 and G7.0, which is in agreement with the 3exon/2intron pattern model of globin gene evolution.
Footnotes
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↵* This work was supported by a NATO International Collaborative Grant (to A. H. J. B., M. B., L. M., and J. V.), a grant from the National Science and Engineering Research Council of Canada (to A. H. J. B.), and a grant from the Leverhulme Trust (to M. B. and P. H.). S. D. is a postdoc fellow of the Fund for Scientific Research Flanders (FWO).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) , , , , , , , and .
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↵** To whom correspondence should be addressed: Dept. of Biochemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium. Tel.: 32-3-820-23-23; Fax: 32-3-820-22-48; E-mail: lmoens@uia.ua.ac.be.
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↵2 P. Hunt, A. H. J. Burr, and M. L. Blaxter, unpublished observations.
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↵3 S. Dewilde, B. Winnepenninckx, Y. Van de Peer, J. Vanfleteren, and L. Moens, unpublished observations.
- Abbreviations:
- Hb(s)
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hemoglobin(s)
- PCR
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polymerase chain reaction
- RT
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reverse transcription
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- Received October 15, 1999.
- Revision received November 29, 1999.
- The American Society for Biochemistry and Molecular Biology, Inc.
