In:
RNA, Cold Spring Harbor Laboratory, Vol. 18, No. 6 ( 2012-06), p. 1244-1256
Abstract:
The compositional and conformational changes during catalytic activation of the spliceosome promoted by the DEAH box ATPase Prp2 are only poorly understood. Here, we show by dual-color fluorescence cross-correlation spectroscopy (dcFCCS) that the binding affinity of several proteins is significantly changed during the Prp2-mediated transition of precatalytic B act spliceosomes to catalytically activated B* spliceosomes from Saccharomyces cerevisiae . During this step, several proteins, including the zinc-finger protein Cwc24, are quantitatively displaced from the B* complex. Consistent with this, we show that Cwc24 is required for step 1 but not for catalysis per se. The U2-associated SF3a and SF3b proteins Prp11 and Cus1 remain bound to the B* spliceosome under near-physiological conditions, but their binding is reduced at high salt. Conversely, high-affinity binding sites are created for Yju2 and Cwc25 during catalytic activation, consistent with their requirement for step 1 catalysis. Our results suggest high cooperativity of multiple Prp2-mediated structural rearrangements at the spliceosome's catalytic core. Moreover, dcFCCS represents a powerful tool ideally suited to study quantitatively spliceosomal protein dynamics in equilibrium.
Type of Medium:
Online Resource
ISSN:
1355-8382
,
1469-9001
DOI:
10.1261/rna.033316.112
Language:
English
Publisher:
Cold Spring Harbor Laboratory
Publication Date:
2012
detail.hit.zdb_id:
1475737-0
SSG:
12
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