Structural studies on Vibrio cholerae ToxR periplasmic and cytoplasmic domains

Chatterjee, Tanaya ; Saha, Rudra Prasad ; Chakrabarti, Pinak (2007) Structural studies on Vibrio cholerae ToxR periplasmic and cytoplasmic domains Biochimica et Biophysica Acta: Proteins & Proteomics, 1774 (10). pp. 1331-1338. ISSN 1570-9639

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The transcription activator ToxR controls the expression of cholera toxin, pilus colonization factor and outer membrane protein in Vibrio cholerae. It binds to the 5'-TTTTGAT-3' tandemly repeated DNA sequence in the cholera toxin promoter region. ToxR is a membrane protein having distinct periplasmic and cytoplasmic domains. The two domains have been cloned, over-expressed and purified for structural studies. The cytoplasmic domain is more compact than the periplasmic domain. The periplasmic domain exists as dimer due to the presence of an interchain disulfide linkage, while the cytoplasmic domain is monomeric in solution implying the importance of the disulfide bond to homodimerize the native ToxR. By replacing one of the cysteines C293 with alanine, using site-directed mutagenesis, a C293A mutant was created at the periplasmic domain to elucidate the role of cysteine in dimerization of ToxR.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Toxr Protein; Transcription Regulation; Cholera Toxin; Periplasmic Domain; Cytoplasmic Domain; Interchain Disulfide Bond; Site-directed Mutagenesis
ID Code:21475
Deposited On:22 Nov 2010 11:18
Last Modified:20 May 2011 09:56

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