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MacRae, Ian J; Zhou, Kaihong; Li, Fei; Repic, Adrian; Brooks, Angela N; Cande, W. Zacheus; Adams, Paul D; Doudna, Jennifer A
Science (American Association for the Advancement of Science), 01/2006, Letnik: 311, Številka: 5758Journal Article
The specialized ribonuclease Dicer initiates RNA interference by cleaving double-stranded RNA (dsRNA) substrates into small fragments about 25 nucleotides in length. In the crystal structure of an intact Dicer enzyme, the PAZ domain, a module that binds the end of dsRNA, is separated from the two catalytic ribonuclease III (RNase III) domains by a flat, positively charged surface. The 65 angstrom distance between the PAZ and RNase III domains matches the length spanned by 25 base pairs of RNA. Thus, Dicer itself is a molecular ruler that recognizes dsRNA and cleaves a specified distance from the helical end.
