PMID: 16216575 , Related PDB ids: 1YYK, 1YYO, 1YYW, 1YZ9

Authors:

Gan J, Tropea JE, Austin BP, Court DL, Waugh DS, Ji X

Title:

Intermediate states of ribonuclease III in complex with double-stranded RNA.

Journal:

Structure. 2005 Oct;13(10):1435-42.

Abstract:

Bacterial ribonuclease III (RNase III) can affect RNA structure and gene expression in either of two ways: as a processing enzyme that cleaves double-stranded (ds) RNA, or as a binding protein that binds but does not cleave dsRNA. We previously proposed a model of the catalytic complex of RNase III with dsRNA based on three crystal structures, including the endonuclease domain of RNase III with and without bound metal ions and a dsRNA binding protein complexed with dsRNA. We also reported a noncatalytic assembly observed in the crystal structure of an RNase III mutant, which binds but does not cleave dsRNA, complexed with dsRNA. We hypothesize that the RNase III*dsRNA complex can exist in two functional forms, a catalytic complex and a noncatalytic assembly, and that in between the two forms there may be intermediate states. Here, we present four crystal structures of RNase III complexed with dsRNA, representing possible intermediates.