Transfer of flexibility between ankyrin repeats in IkappaB* upon formation of the NF-kappaB complex.

ABSTRACT: The mechanism of inhibition of the transcriptional activator nuclear factor kappaB (NF-kappaB) by the inhibitor IkappaB* is central to the understanding of the control of transcriptional activity via this widely employed pathway. Previous studies suggested that IkappaB* , a modular protein with an NF-kappaB binding domain consisting of six ankyrin repeat domains (ANKs), shows differential flexibility, with ANK 1-4 apparently more rigid in solution in the absence of NF-kappaB than ANK 5 and 6. Here we report NMR studies that confirm the enhanced flexibility of ANK 5 and 6 in free IkappaB* . Upon binding of NF-kappaB, ANK 5 and 6 become well structured and rigid, but, somewhat surprisingly, other domains of the IkappaB* , which were relatively rigid in the free protein, become significantly

SUBMITTER: Sue SC 

PROVIDER: S-EPMC2603615 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature