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Biological Chemistry

Editor-in-Chief: Brüne, Bernhard

Editorial Board Member: Buchner, Johannes / Ludwig, Stephan / Sies, Helmut / Turk, Boris / Wittinghofer, Alfred

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The spliceosome: a ribozyme at heart?

Saba Valadkhan1

1Center for RNA Molecular Biology, Case Western Reserve University, Cleveland, OH 44106, USA

Citation Information: Biological Chemistry. Volume 388, Issue 7, Pages 693–697, ISSN (Online) 14316730, ISSN (Print) 14374315, DOI: 10.1515/BC.2007.080, July 2007

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The spliceosome, the multi-megadalton molecular machine that performs splicing, consists of over 200 different proteins and five small nuclear RNAs (snRNAs). Extensive mechanistic and structural similarities to self-splicing group II introns, large ribozymes found in prokaryotes and lower eukaryotes that catalyze an identical reaction, strongly suggest that the spliceosomal RNAs are in fact the catalytic components of the spliceosome. Of the five spliceosomal RNAs, U2 and U6 are the only ones that are absolutely required for both steps of splicing. These two snRNAs form an elaborate base-paired complex that might in fact constitute the active site of the spliceosome.

Keywords: active site; catalysis; ribozyme; splicing mechanism; U6 snRNA

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