INVESTIGADORES
WOLOSIUK Alejandro
congresos y reuniones científicas
Título:
Secondary structure changes of 2-Cys peroxiredoxin are associated to the formation of aggregates
Autor/es:
FERRERO, D.; ARAN, M.; WOLOSIUK, A.; WOLOSIUK, R.A.
Lugar:
Mar del Plata
Reunión:
Congreso; XLIII Reunión Nacional de la SAIB; 2007
Institución organizadora:
Sociedad Argentina de Investigacion Bioquimica y Biologia Molecular
Resumen:
2-Cys peroxiredoxins (2-Cys Prx) constitute a subfamily of ubiquitous
peroxidases. The composition of the milieu influences the assembly of
2-Cys Prx dimers into decamers, and the latter into high molecular mass
oligomers that form large filamentous oligomers in mammalian cells.
Although a key to understanding the biological significance of
aggregation is the characterization of the underlying mechanism, factors
that drive 2-Cys Prx out of the solution are barely known. We found
that the rapeseed counterpart aggregates at pH 6.0 but returns to
solution either by the reversal of pH to 8 or at pHs beyond 5.5.
Circular dichroism spectroscopy reveals that the aggregation was
accompanied by changes in the proportion of secondary structures;
b_enriched structures form at pH 6.0 while the contribution of a-helical
structures increases when the pH is above 6.5 or falls below 5.5. In
line with these transitions, the dynamic light scattering analysis of
2-Cys Prx uncovers that small sized oligomers build up high molecular
mass species at pH 6. On the other hand, transmission electron
microscopy reveals that the whole architecture is represented by
globular structures of variable diameter extending for several
nanometers in legth. Taking together these data indicate that the
formation of b-sheet structures may be essential for the reversible
formation of aggregates.