Self-assembly and structural characterization of Echinococcus granulosus antigen B recombinant subunit oligomers.
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.
Monteiro
Karina M
KM
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.
Scapin
Sandra M N
SM
Navarro
Marcos V A S
MV
Zanchin
Nilson I T
NI
Cardoso
Mateus B
MB
da Silveira
Nádya P
NP
Gonçalves
Paulo F B
PF
Stassen
Hubert K
HK
Zaha
Arnaldo
A
Ferreira
Henrique B
HB
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
D000947:Antigens, Helminth; D001704:Biopolymers; D011994:Recombinant Proteins