INIBIOLP   05426
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE LA PLATA "PROF. DR. RODOLFO R. BRENNER"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
First approximation to the study of a tandemly repeated protein: the case of ABA-1A from Ascaris suum
Autor/es:
B. CÓRSICO; RODRIGUEZ, S.; FRANCHINI GR; BELGAMO J
Reunión:
Congreso; Reunion anual Sociedad Arg. Biofisica; 2018
Resumen:
Tandemly repetitive polyproteins (TRPs) are rare in nature. They are produced aslarge precursor polypeptides, comprising repeated units of similar or identicalamino acid sequence that are post-translationally cleaved into a dozen or socopies of functionally similar proteins. The polyprotein allergens/antigens ofnematodes (NPAs) belong to this family, are small, helix-rich proteins, and have noknown structural counterparts in other phyla. The NPAs present in Ascaris suum(ABA) are cleaved posttranslationally into multiple ~15 kDa protein subunits whichmay have similar or different functions. It is important to note that they alsorepresent a novel class of lipid binding proteins from helminths group. ABA-1A, asingle subunit of this family of proteins, is found in high amounts both in thepseudocelomic fluid of adult worms and in the excretion/secretion products fromall parasitic stages. Recently, the structure of ABA-1A has been solved showingtwo binding sites with different characteristics. The protein adopts a novel sevenhelical fold comprising a long central helix that participates in two hollow fourhelical bundles on either side (Meenan et al., 2011 doi:10.1371/journal.pntd.0001040). Although structural and functional characterisation has been performedon the single subunit, ABA-1A, there are no reports on the polyprotein array. In thisproject we aim at getting further insight into the unusual translation process ofthese proteins. To this end we designed, constructed and expressed a tandemprotein composed of two ABA-1A subunits. Preliminary analysis usingspectroscopic techniques (fluorescence and CD) have shown that there are nodifferences in the secondary and tertiary structure between the tandem proteinand the ABA-1A subunit alone. These results would suggest that there are almostno interactions between subunits during polypeptide folding in vivo when it isbeing synthesized.AcknowldegmentsWe thank to PhD. José María Delfino and Lucrecia Curto from IQUIFIB, School of Pharmacy andBiochemistry, University of Buenos Aires for their assistance with spectropolarimeter JASCO J-810.