Correct folding is critical for the biological activities of proteins. As a contribution to a better understanding of the protein (un)folding problem, we studied the effect of temperature and of urea on peptostreptococcal Protein L destructuration. We performed standard molecular dynamics simulations at 300 K, 350 K, 400 K, and 480 K, both in 10 M urea and in water. Protein L followed at least two alternative unfolding pathways. Urea caused the loss of secondary structure acting preferentially on the β-sheets, while leaving the α-helices almost intact; on the contrary, high temperature preserved the β-sheets and led to a complete loss of the a-helices. These data suggest that urea and high temperature act through different unfolding mechanisms, and protein secondary motives reveal a differential sensitivity to various denaturant treatments. As further validation of our results, replica-exchange molecular dynamics simulations of the temperature-induced unfolding process in the presence of urea were performed. This set of simulations allowed us to compute the thermodynamical parameters of the process and confirmed that, in the configurational space of Protein L unfolding, both of the above pathways are accessible, although to a different relative extent.

Characterization of the protein unfolding processes induced by urea and temperature / A. Guerini Rocco, L. Mollica, P. Ricchiuto, A. M. Baptista, E. Gianazza, I. Eberini. - In: BIOPHYSICAL JOURNAL. - ISSN 0006-3495. - 94:6(2008), pp. 2241-2251. [10.1529/biophysj.107.115535]

Characterization of the protein unfolding processes induced by urea and temperature

A. Guerini Rocco
Primo
;
L. Mollica;P. Ricchiuto;E. Gianazza
Penultimo
;
I. Eberini
Ultimo
2008

Abstract

Correct folding is critical for the biological activities of proteins. As a contribution to a better understanding of the protein (un)folding problem, we studied the effect of temperature and of urea on peptostreptococcal Protein L destructuration. We performed standard molecular dynamics simulations at 300 K, 350 K, 400 K, and 480 K, both in 10 M urea and in water. Protein L followed at least two alternative unfolding pathways. Urea caused the loss of secondary structure acting preferentially on the β-sheets, while leaving the α-helices almost intact; on the contrary, high temperature preserved the β-sheets and led to a complete loss of the a-helices. These data suggest that urea and high temperature act through different unfolding mechanisms, and protein secondary motives reveal a differential sensitivity to various denaturant treatments. As further validation of our results, replica-exchange molecular dynamics simulations of the temperature-induced unfolding process in the presence of urea were performed. This set of simulations allowed us to compute the thermodynamical parameters of the process and confirmed that, in the configurational space of Protein L unfolding, both of the above pathways are accessible, although to a different relative extent.
Settore BIO/14 - Farmacologia
Settore BIO/12 - Biochimica Clinica e Biologia Molecolare Clinica
Article (author)
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/57288
Citazioni
  • ???jsp.display-item.citation.pmc??? 17
  • Scopus 68
  • ???jsp.display-item.citation.isi??? 69
social impact