Mukherjee, Kakoli and Nagai, Hiroki and Shimamoto, Nobuo and Chatterji, Dipankar (1999) GroEL is involved in activation of Escherichia coli RNA polymerase devoid of the \omega subunit in vivo. In: European Journal of Biochemistry, 266 (1). pp. 228-235.
Highly purified Escherichia coli RNA polymerase contains a small subunit termed \omega that has a molecular mass of 10 105 Da and is comprised of 91 amino acids. E. coli strains lacking \omega (\omega-less) are viable, but exhibit a slow-growth phenotype. Renaturation of RNA polymerase isolated from an \omega-less mutant, in the presence of \omega, resulted in maximum recovery of activity. The \omega-less RNA polymerase from \omega-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 $\sigma^7^0$ to generate the fully functional holoenzyme. However, when GroEL was removed, the enzyme was irreversibly nonfunctional and was unable to bind to $\sigma^7^0$. The damaged enzyme regained activity after going through a cycle of denaturation and reconstitution in the presence of \omega or GroEL. GroES was found to have an inhibitory effect on the core-$\sigma^7^0$ association unlike the \omega subunit. The \omega subunit may therefore be needed for stabilization of the structure of RNA polymerase.
|Item Type:||Journal Article|
|Additional Information:||The copyright belongs to Blackwell Science.|
|Keywords:||Escherichia coli;RNA polymerase;amino acids|
|Department/Centre:||Division of Biological Sciences > Molecular Biophysics Unit|
|Date Deposited:||25 Jan 2005|
|Last Modified:||19 Sep 2010 04:15|
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