Estudo termodinamico da dissociação do virus do mosaico do tabaco (TMV) por pressão e baixa temperatura

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

We investigated the effect of low temperature and urea combined with high pressure on Tobacco Mosaic Virus (TMV). The evaluation of its aggregation state and denaturation process was studied using spectroscopic methods. The incubation at 2.5 kbar and ?0 DEGREES?C induced significative dissociation. Under such conditions extensive denaturation did occur. At different TMV concentrations the ?p IND. ½? was 1.2 kbar. This result shows absence of concentration dependence of TMV dissociation by pressure, that can be explained by the TMV association energy heterogeneity. The apparent enthalpy and entropy of dissociation (?delta??H POT. *, IND. dis? and ?delta??S POT. *, IND. dis?) were ?6,9 and ?15,3 kcal/mol of subunit respectively, indicating that the TMV association is an entropicaly driven process. The apparent free energy of stabilization given by the presence of RNA is at least ?1,7 kcal/mol of subunit. High pressure induced remarkable TMV denaturation in the presence of 2.5 M urea, with a volume change of ?105 mL/mol of denaturated subunit. The apparent enthalpy and entropy of denaturation (?delta??H POT. *, IND. den? and T?delta??S POT. *, IND. den?) by 1.75 M urea at 2.5 kbar was ?11.1 and ?10.2 kcal/mol of subunit, respectively, demonstrating that the TMV protein coat presents an apparent free energy of denaturation by urea close to zero... Note: The complete abstract is available with the full electronic digital thesis or dissertations

ASSUNTO(S)

baixas temperaturas pressão hidrostatica virus de plantas

ACESSO AO ARTIGO

Documentos Relacionados