Analisis estructura, funcion de interfases proteina, proteinay acido nucleico, proteina en un virus esferico, el virus diminuto del raton
- Autores: Juan Javier Reguera Vidaeche
- Directores de la Tesis: Mauricio García Mateu (dir. tes.)
- Lectura: En la Universidad Autónoma de Madrid ( España ) en 2004
- Idioma: español
- Tribunal Calificador de la Tesis: Luis Enjuanes (presid.), Luis Menéndez Arias (secret.), José María Almendral del Río (voc.), Antonio L. Llamas Sáiz (voc.), José Antonio Melero Fondevilla (voc.)
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- Resumen
ABSTRACT / RESUMEN EN INGLÉS.
The assembly and stability of a nonenveloped spherical virion must depend on the establishment of a number of non-covalent interactions between the protein subunits that form its capsid. Interactions between the capsid and the enclosed viral nucleic acid could also contribute to the stability of the virion. This doctoral thesis presents the results of a thorough mutational analysis of the protein-protein interfaces between the subunits of a viral capsid, and of the visible protein-nucleic acid interfaces in the virion. As a model we have used the parvovirus minute virus of mice, one of the structurally simplest spherical virions known. The analysis has allowed to identify amino acid residues at the protein subunit interfaces that are involved in capsid assembly, stability and/or conformation, and those at the capsid-nucleic acid interfaces that are involved in nucleic acid packaging, virion stability and/or infectivity. The specific results obtained can be summarized as follows.
1) Removal of some interactions predicted to be important for holding trimers of the capsid protein together led to the isolation of stable trimeric structures, and confirmed that the MVM capsid assembles through trimeric intermediates.
2) Systematic mutation to alanine of 28 selected residues at the intertrimer interfaces showed that only a few residues per subunit (W203, F247, W543, Y522, T249, Q129, K153) are individually critical for MVM capsid assembly.
All but one of these residues correspond to those involved in the highest number of hydrophobic contacts or in hydrogen bonds or salt bridges between trimers. The vast majority of the interfacial residues are not individually needed for capsid assembly or contribute substantially to capsid stability against dissociation.
3) The interfacial residues located around the base of the pores at the 5-fold symmetry axes of the capsid (V40, S43, N149, N170, D263, F526) are also n
