Characterization of purified human Bact spliceosomal complexes reveals compositional and morphological changes during spliceosome activation and first step catalysis.

ABSTRACT: To better understand the compositional and structural dynamics of the human spliceosome during its activation, we set out to isolate spliceosomal complexes formed after precatalytic B but prior to catalytically active C complexes. By shortening the polypyrimidine tract of the PM5 pre-mRNA, which lacks a 3' splice site and 3' exon, we stalled spliceosome assembly at the activation stage. We subsequently affinity purified human B(act) complexes under the same conditions previously used to isolate B and C complexes, and analyzed their protein composition by mass spectrometry. A comparison of the protein composition of these complexes allowed a fine dissection of compositional changes during the B to B(act) and B(act) to C transitions, and comparisons with the Saccharomyces cerevisiae B(act) c

SUBMITTER: Bessonov S 

PROVIDER: S-EPMC2995400 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature