GroEL is involved in activation of Escherichia coli RNA polymerase devoid of the σ subunit in vivo

Mukherjee, Kakoli ; Nagai, Hiroki ; Shimamoto, Nobuo ; Chatterji, Dipankar (1999) GroEL is involved in activation of Escherichia coli RNA polymerase devoid of the σ subunit in vivo European Journal of Biochemistry, 266 (1). pp. 228-235. ISSN 0014-2956

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Official URL: http://onlinelibrary.wiley.com/doi/10.1046/j.1432-...

Related URL: http://dx.doi.org/10.1046/j.1432-1327.1999.00848.x

Abstract

Highly purified Escherichia coli RNA polymerase contains a small subunit termed ω that has a molecular mass of 10 105 Da and is comprised of 91 amino acids. E. coli strains lacking ω (ω-less) are viable, but exhibit a slow-growth phenotype. Renaturation of RNA polymerase isolated from an ω-less mutant, in the presence of ω, resulted in maximum recovery of activity. The ω-less RNA polymerase from ω-less strains recruits the chaperonin, GroEL (unlike the wild-type enzyme), suggesting a structural deformity of the mutant enzyme. The GroEL-containing core RNA polymerase interacts efficiently with σ70 to generate the fully functional holoenzyme. However, when GroEL was removed, the enzyme was irreversibly nonfunctional and was unable to bind to σ70. The damaged enzyme regained activity after going through a cycle of denaturation and reconstitution in the presence of ω or GroEL. GroES was found to have an inhibitory effect on the core-σ70 association unlike the ω subunit. The ω subunit may therefore be needed for stabilization of the structure of RNA polymerase.

Item Type:Article
Source:Copyright of this article belongs to John Wiley and Sons.
Keywords:Activation; GroEL; Renaturation; RNA Polymerase (ω-less); σ70 Interaction
ID Code:6296
Deposited On:20 Oct 2010 11:15
Last Modified:30 Sep 2011 10:15

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