Major conformational change in the complex SF3b upon integration into the spliceosomal U11/U12 di-snRNP as revealed by electron cryomicroscopy

Monika M Golas; Bjoern Sander; Cindy L Will; Reinhard Lührmann; Holger Stark

doi:10.1016/j.molcel.2005.02.016

Major conformational change in the complex SF3b upon integration into the spliceosomal U11/U12 di-snRNP as revealed by electron cryomicroscopy

Mol Cell. 2005 Mar 18;17(6):869-83. doi: 10.1016/j.molcel.2005.02.016.

Authors

Monika M Golas¹, Bjoern Sander, Cindy L Will, Reinhard Lührmann, Holger Stark

Affiliation

¹ Department of Cellular Biochemistry and Research Group of 3D Electron Cryomicroscopy, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany.

PMID: 15780942
DOI: 10.1016/j.molcel.2005.02.016

Abstract

In some eukaryotes, a minor class of introns is removed by the U12-dependent spliceosome, which contains the small nuclear ribonucleoprotein (snRNP) heterodimer U11/U12. The U11/U12 di-snRNP forms a molecular bridge that functionally pairs the intron ends of the pre-mRNA. We have determined the three-dimensional (3D) structure of the human U11/U12 di-snRNP by single particle electron cryomicroscopy using angular reconstitution and random conical tilt. SF3b, a heteromeric protein complex functionally important for branch site recognition, was located in the U11/U12 di-snRNP by antibody labeling and by identification of structural domains of SF3b155, SF3b49, and p14. The conformation of SF3b bound to the U11/U12 di-snRNP differs from that of isolated SF3b: upon integration into the di-snRNP, SF3b rearranges into a more open form. The manner in which SF3b is integrated in the U11/U12 di-snRNP has important implications for branch site recognition. Furthermore, a putative model of the pre-mRNA binding to the U11/U12 di-snRNP is proposed.

Publication types

Comparative Study
Research Support, Non-U.S. Gov't

MeSH terms

Cryoelectron Microscopy
Dimerization
HeLa Cells
Humans
Immunoglobulin G / immunology
Immunoglobulin G / metabolism
Introns / genetics*
Multiprotein Complexes
Phosphoproteins / chemistry*
Phosphoproteins / genetics
Phosphoproteins / metabolism
Protein Conformation*
RNA Splicing
RNA Splicing Factors
RNA-Binding Proteins / chemistry*
RNA-Binding Proteins / genetics
RNA-Binding Proteins / metabolism
Ribonucleoprotein, U2 Small Nuclear / chemistry*
Ribonucleoprotein, U2 Small Nuclear / genetics
Ribonucleoprotein, U2 Small Nuclear / metabolism
Ribonucleoproteins, Small Nuclear / chemistry*
Ribonucleoproteins, Small Nuclear / genetics
Ribonucleoproteins, Small Nuclear / metabolism
Spliceosomes / chemistry*

Substances

Immunoglobulin G
Multiprotein Complexes
Phosphoproteins
RNA Splicing Factors
RNA-Binding Proteins
Ribonucleoprotein, U2 Small Nuclear
Ribonucleoproteins, Small Nuclear
SF3B1 protein, human
SF3B4 protein, human
U11 small nuclear ribonucleoprotein, human
U11-U12 small nuclear ribonucleoprotein
U2 small nuclear ribonucleoprotein p14