title: Self-assembly and structural characterization of Echinococcus granulosus antigen B recombinant subunit oligomers.
abstract: Echinococcus granulosus antigen B is an oligomeric protein of 120-160 kDa composed by 8-kDa (AgB8) subunits. Here, we demonstrated that the AgB8 recombinant subunits AgB8/1, AgB8/2 and AgB8/3 are able to self-associate into high order homo-oligomers, showing similar properties to that of parasite-produced AgB, making them valuable tools to study AgB structure. Dynamic light scattering, size exclusion chromatography and cross-linking assays revealed approximately 120- to 160-kDa recombinant oligomers, with a tendency to form populations with different aggregation states. Recombinant oligomers showed helical circular dichroism spectra and thermostability similar to those of purified AgB. Cross-linking and limited proteolysis experiments indicated different degrees of stability and compactness between the recombinant oligomers, with the AgB8/3 one showing a more stable and compact structure. We have also built AgB8 subunit structural models in order to predict the surfaces possibly involved in electrostatic and hydrophobic interactions during oligomerization.
authors.affiliation: Laboratório de Biologia Molecular de Cestódeos, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Cx. Postal 15005, 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Karina M
authors.initials: KM
authors.lastname: Monteiro
authors.forename: Sandra M N
authors.initials: SM
authors.lastname: Scapin
authors.forename: Marcos V A S
authors.initials: MV
authors.lastname: Navarro
authors.forename: Nilson I T
authors.initials: NI
authors.lastname: Zanchin
authors.forename: Mateus B
authors.initials: MB
authors.lastname: Cardoso
authors.forename: Nádya P
authors.initials: NP
authors.lastname: da Silveira
authors.forename: Paulo F B
authors.initials: PF
authors.lastname: Gonçalves
authors.forename: Hubert K
authors.initials: HK
authors.lastname: Stassen
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Zaha
authors.forename: Henrique B
authors.initials: HB
authors.lastname: Ferreira
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000947:Antigens, Helminth / Q000737:chemistry* / Q000276:immunology; D001704:Biopolymers; D002850:Chromatography, Gel; D002942:Circular Dichroism; D048209:Echinococcus granulosus / Q000276:immunology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence; D055672:Static Electricity
chemical_list: D000947:Antigens, Helminth; D001704:Biopolymers; D011994:Recombinant Proteins