title: Recombinant functional multidomain hemoglobin from the gastropod Biomphalaria glabrata.
abstract: The extracellular hemoglobin multimer of the planorbid snail Biomphalaria glabrata, intermediate host of the human parasite Schistosoma mansoni, is presumed to be a 1.44 MDa complex of six 240 kDa polypeptide subunits, arranged as three disulfide-bridged dimers. The complete amino acid sequence of two subunit types (BgHb1 and BgHb2), and the partial sequence of a third type (BgHb3) are known. Each subunit encompasses 13 paralogus heme domains, and N-terminally a smaller plug domain responsible for subunit dimerization. We report here the recombinant expression of different functional fragments of BgHb2 in Escherichia coli, and of the complete functional subunits BgHb1 and BgHb2 in insect cells; BgHb1 was also expressed as disulfide-bridged dimer (480 kDa). Oxygen-binding measurements of the recombinant products show a P(50) of about 7 mmHg and the absence of a significant cooperativity or Bohr effect. The covalently linked dimer of BgHb1, but not the monomer, is capable to form aggregates closely resembling native BgHb molecules in the electron microscope.
authors.affiliation: Institute of Zoology, Johannes Gutenberg University, Mainz, Germany.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Moeller
authors.forename: Ralf
authors.initials: R
authors.lastname: Dürr
authors.forename: Ladan
authors.initials: L
authors.lastname: Sarraf-Zadeh
authors.forename: Sabrina
authors.initials: S
authors.lastname: Keller
authors.forename: Stefanie
authors.initials: S
authors.lastname: Heinz
authors.forename: Nadja
authors.initials: N
authors.lastname: Hellmann
authors.forename: Arne
authors.initials: A
authors.lastname: Moeller
authors.forename: Bernhard
authors.initials: B
authors.lastname: Lieb
authors.forename: Jürgen
authors.initials: J
authors.lastname: Markl
mesh_terms: D000818:Animals; D001700:Biomphalaria / Q000737:chemistry* / Q000469:parasitology; D006454:Hemoglobins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D010100:Oxygen / Q000378:metabolism; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012550:Schistosoma mansoni / Q000502:physiology
chemical_list: D006454:Hemoglobins; D021122:Protein Subunits; D011994:Recombinant Proteins; D010100:Oxygen