Multiphasic denaturation of the λ repressor by urea and its implications for the repressor structure

Banik, Utpal ; Saha, Rina ; Mandal, Nitai C. ; Bhattacharyya, Bhabatarak ; Roy, Siddhartha (1992) Multiphasic denaturation of the λ repressor by urea and its implications for the repressor structure European Journal of Biochemistry, 206 (1). pp. 15-21. ISSN 0014-2956

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Official URL: http://onlinelibrary.wiley.com/doi/10.1111/j.1432-...

Related URL: http://dx.doi.org/10.1111/j.1432-1033.1992.tb16896.x

Abstract

Urea denaturation of the λ repressor has been studied by fluorescence and circular dichroic spectroscopies. Three phases of denaturation could be detected which we have assigned to part of the C-terminal domain, N-terminal domain and subunit dissociation coupled with further denaturation of the rest of the C-terminal domain at increasing urea concentrations. Acrylamide quenching suggests that at least one of the three tryptophan residues of the λ repressor is in a different environment and its emission maximum is considerably blue-shifted. The transition in low urea concentration (midpoint approximately 2 M) affects the environment of this tryptophan residue, which is located in the C-terminal domain. Removal of the hinge and the N-terminal domain shifts this transition towards even lower urea concentrations, indicating the presence of interaction between hinge on N-terminal and C-terminal domains in the intact repressor.

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Source:Copyright of this article belongs to John Wiley and Sons.
ID Code:43175
Deposited On:10 Jun 2011 07:25
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