Actas de congresos
The influence of both urea and 2,2,2
Fecha
2013-02-05Registro en:
Biophysical Society 57th Annual Meeting: San Francisco, California, February 2-6, 2013
Autor
Barbosa, Leandro Ramos Souza
Brito, Lenilson Tôrres
Institución
Resumen
The influence of external agents on proteins function and structure is essential
to elucidate the unfolding pathways and self-assemble properties. The knowledge
of the protein amyloid fibril formation process is important due to the
fields that this subjected is related, in particular for the neurodegenerative
disorders. In the present work we studied the influence of both urea and
2,2,2-Trifluoroethanol (TFE) and temperature on the structure and proteinprotein
interactions of Bovine Serum Albumin (BSA), by means of UV-Vis
spectroscopy, static fluorescence and small angle X-ray scattering technique.
The experiments were performed in samples composed by 10 and 3 mg/ml of
BSA at pH 5.8, near the protein pI. First, Thioflavin-T fluorescence measurements
indicated that urea, in the absence of TFE, was able to increase the
amyloid fibril formation of BSA at 45oC and increasing the urea concentration
the rate of amyloid fibril formation also increases. Concerning the presence
of TFE, SAXS data suggest that BSA tridimensional structure is not
altered by the presence of TFE 5% and 10% v/v in all studied protein concentrations.
Interestingly, the presence of TFE on the urea-containing BSA also
increases the rate of amyloid fibril formation, as compared to the TFE-free
system, indicating that TFE can catalyze the amyloid-fibril formation. The
presence of TFE 20% v/v, however, induces the formation of aggregates,
but at this time we were not able to infer if such aggregates are amyloidlike
or amorphous. Taking together, the results give support to infer that
BSA can for fibrils in the presence of urea at 45oC and TFE can act as a stabilizer
or as a denaturant agent for BSA.