Structural characterization by SAXS and CryoEM of P9-1, the major viroplasm component of Mal de Río Cuarto virus (MRCV)

GABRIELA LLAUGER; FACUNDO A. GOLDBAUM; LISANDRO H. OTERO; ROBERTO MALERO; GABRIELA SYCZ; MARIANA DEL VAS; CRISTIÁN HUCK IRIART; DEMIAN MONTI; JOSÉ M. CARAZO

Campinas

Congreso; 28th Annual User Meeting LNLS/CNPEM; 2018

LNLS-CNPEM

Malde Río Cuarto virus (MRCV, Fijivirus, Reoviridae) causes the most importantmaize disease in Argentina. The virus replicates in cytoplasmic inclusionbodies called viroplasms composed by non-structural virus proteins P9-1 and P6.P9-1 is a 45 kDa protein that has ATPase activity, which is able to bind ssRNAand to self-assemble giving rise to homomultimers [1,2].  In this work we will show preliminary structuralcharacterization of P9-1 by using two complementary techniques: Small Angle Xray Scattering (SAXS) and Cryo-Electron Microscopy (Cryo-EM). Additionalexperiments included the presence of ATP and/or RNA in order to evaluatechanges in the structure. Accordingto CryoEM assays, quaternary structures consisting of 10 and 12 monomers wereobserved. Experimental SAXS patterns were fitted by using the combination ofATSAS package [3] and python scripting in order to set up each protein complexusing Cryo-EM volume information of the monomer as building block. Ourpreliminary results showed that SAXS patterns were compatible with cylindrical objectscomposed by the stacking of a five subunits ring. Theaim of this work is to provide structural information in order to understandthe function of P9-1 complexes in the presence of ATP and ssARN. [1]Dumón, A.D.; Argüello Caro, E.B.; Mattio, M.F.; Alemandri, M.F.; del Vas, M.;Truol, G. Bulletin of entomological research, 108(2), 232-240 (2018)[2] Maroniche, G.A.; Mongelli, V.C.; Llauger, G.;Alfonso, V.; Taboga, O.; del Vas, M. Virology, 430(2), 81-89, (2012)[3] Franke, D.; Petoukhov, M.V.; Konarev, P.V.;Panjkovich, A.; Mertens, H.D.I.; Kikhney, A.G.; Haijzadeh, N.R.; Franklin,J.M.; Jeffries, C.M.; Svergun, D.I. J. Appl. Cryst 50, 1212-1225 (2017)