Intermediate states of ribonuclease III in complex with double-stranded RNA.
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.
Gan
Jianhua
J
Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA.
Tropea
Joseph E
JE
Austin
Brian P
BP
Court
Donald L
DL
Waugh
David S
DS
Ji
Xinhua
X
D001483:Base Sequence; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics; D005583:Fourier Analysis; D008956:Models, Chemical; D008958:Models, Molecular; D009154:Mutation; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D021122:Protein Subunits; D012330:RNA, Double-Stranded / Q000737:chemistry / Q000378:metabolism*; D043244:Ribonuclease III / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D013059:Spectrum Analysis, Raman; D013698:Templates, Genetic; D014961:X-Ray Diffraction
D021122:Protein Subunits; D012330:RNA, Double-Stranded; D043244:Ribonuclease III