pubmed:abstractText |
A key step in the activation of interferon-inducible antiviral kinase PKR involves differential binding of viral double-stranded RNA (dsRNA) to its two structurally similar N-terminal dsRNA binding motifs, dsRBM1 and dsRBM2. We show here, using NMR spectroscopy, that dsRBM1 with higher RNA binding activity exhibits significant motional flexibility on a millisecond timescale as compared with dsRBM2 with lower RNA binding activity. We further show that dsRBM2, but not dsRBM1, specifically interacts with the C-terminal kinase domain. These results suggest a dynamically tuned dsRNA binding mechanism for PKR activation, where motionally more flexible dsRBM1 anchors to dsRNA, thereby inducing a cooperative RNA binding for dsRBM2 to expose the kinase domain.
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pubmed:affiliation |
Structural Biology Program and Department of Cancer Biology, Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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