HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article ACCEPTED PREPRINT Full Text (PDF) All Versions of this Article: ps.036558.108v1 17/10/1653    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Dewilde, S. Articles by Moens, L. PubMed PubMed Citation Articles by Dewilde, S. Articles by Moens, L. Social Bookmarking                   What's this?

The hemoglobins of the trematodes Fasciola hepatica and Paramphistomum epiclitum. A molecular biological, physico-chemical, kinetic and vaccination study.

¹ University of Antwerp;
² INSERM, Unite U4779;
³ INSERM Uinite U4779;
⁴ Ghent University;
⁵ University of Genova;
⁶ University of Milano

(RECEIVED May 20, 2008; ACCEPTED June 20, 2008)

The trematode Fasciola hepatica (Fa. he.), is a common parasite of human and livestock. The hemoglobin (Hb) of Fa.he., a potential immunogen, was chosen for characterization in search for an effective vaccine. Characterization of trematode Hbs show that they are intracellular single-domain globins with the following remarkable features: (i) Fa.he. expresses two Hb isoforms that differ at two amino-acid sites (F1: 119Y/123Q; F2: 119F/123L). Both isoforms are mono-acetylated at their N-termini; (ii) the genes coding for Fa.he. and Paramphistomum epiclitum (Pa.ep.) Hbs are interrupted by two introns at the conserved positions B12.2 and G7.0.; (iii) UV/VIS and resonance Raman spectroscopy identify the recombinant Fa.he. HbF2 as a pentacoordinated high-spin ferrous Hb; (iv) electron paramagnetic resonance spectroscopy of cyano-met Fa.he. HbF2 proves that the endogenously bound imidazole has no imidazolate character; (v) the major structural determinants of the globin fold are present, they contain a TyrB10/TyrE7 residue pair on the distal side. Although such distal site pair is a signature for high oxygen affinity, as shown for Pa.ep. Hb, the oxygen-binding rate parameters for Fa.he. Hb are intermediate between those of myoglobin and those of other trematode Hbs; (vi) the 3D structure of recombinant Fa.he. HbF2 from this study closely resembles the 3D structure of Pa.ep determined earlier. The set of distal site polar interactions observed in Pa.ep. Hb is matched with small but significant structural adjustments; (vii) despite the potential immunogenic character of the fluke Hb, vaccination of calves with recombinant Fa.he. HbF2 failed to promote protection against parasitic infection.

Keywords: Structure/function studies; Heme proteins; Protein crystallization; Other Spectroscopies; Protein Sequencing, Modification, Mass Spectroscopy; Kinetics; Protein sequencing via cDNA/genomic DNA; Expression systems; fluke; vaccination

⁷ E-mail: sylvia.dewilde{at}ua.ac.be

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?