The biological dimer of Aquifex aeolicus ribonuclease III (E110K) in complex with dsRNA (Aa-E110K•dsRNA) (Blaszczyk J, Gan J, Tropea JE, Court DL, Waugh DS, and Ji X. Structure 2004; 12:457-466. Abstract). The dsRNA is illustrated as stick models. One chain of the Aa-RNase III dimer is colored in yellow [endonuclease domain (endoND)] and green [dsRNA-binding domain (dsRBD)] and the other in cyan (endoND) and blue (dsRBD). The signature motif of RNase III is highlighted in red.