title: Structural characterization of hemoglobins from Monilifera and Frenulata tubeworms (Siboglinids): first discovery of giant hexagonal-bilayer hemoglobin in the former "Pogonophora" group.
abstract: Siboglinids are symbiotic polychete annelids having hemoglobins as essential oxygen- and sulfide-carriers for their endosymbiotic bacteria. We analyzed the structure of the hemoglobins from two species of siboglinids: the monilifera Sclerolinum contortum and the frenulata Oligobrachia webbi (i.e. haakonmosbiensis) from Norwegian cold seeps. Measured by Multi-Angle Laser Light Scattering (MALLS), Sclerolinum shows a 3190+/-50 kDa hexagonal bilayer hemoglobin (HBL-Hb) and a 461+/-46 kDa ring-Hb, just as vestimentifera, whereas Oligobrachia has a 409+/-3.7 kDa ring-Hb only. Electrospray Ionization-Mass Spectrometry (ESI-MS) showed Sclerolinum HBL-Hb composed of seven monomeric globins (15-16 kDa), three disulfide-bonded globin heterodimers and three linkers. The heterodimers always contain globin-b (15814.4+/-1.5 Da). Sclerolinum ring-Hb is composed of globins and dimers with identical masses as its HBL-Hb, but lacks linkers. Oligobrachia ring-Hb has three globin monomers (14-15 kDa) only, with no disulfide-bonded dimers. Comparison of Sclerolinum hemoglobins between Storegga and Haakon Mosby Mud Volcano, using the normalized height of deconvoluted ESI-MS peaks, shows differences in globin monomers abundances that could reflect genetic differences or differential gene expression between distinct seep populations. The discovery of HBL-Hb in Sclerolinum is a new element supporting the hypothesis of monilifera being phylogenetically more closely related to vestimentifera, than to frenulata.
authors.affiliation: UPMC Université Paris VI, UMR 7144, Equipe Ecophysiologie des Invertébrés Marins des Milieux Extrêmes, Station Biologique de Roscoff, Place Georges Teissier, B.P 74. F-29682 Roscoff-cedex, France. Cedric.Meunier@awi.de
authors.forename: Cédric
authors.initials: C
authors.lastname: Meunier
authors.forename: Ann C
authors.initials: AC
authors.lastname: Andersen
authors.forename: Matthieu
authors.initials: M
authors.lastname: Bruneaux
authors.forename: Dominique
authors.initials: D
authors.lastname: Le Guen
authors.forename: Peran
authors.initials: P
authors.lastname: Terrier
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Leize-Wagner
authors.forename: Franck
authors.initials: F
authors.lastname: Zal
mesh_terms: D000818:Animals; D000845:Annelida / Q000737:chemistry / Q000378:metabolism*; D006454:Hemoglobins / Q000737:chemistry* / Q000378:metabolism*; D008027:Light; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D008970:Molecular Weight; D010802:Phylogeny; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D012542:Scattering, Radiation; D020539:Sequence Analysis, Protein; D013045:Species Specificity
chemical_list: D006454:Hemoglobins