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Crystal structure of a core spliceosomal protein interface

Matthew J Schellenberg1, Ross A Edwards, Dustin B Ritchie

  • 1Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.

Proceedings of the National Academy of Sciences of the United States of America
|January 25, 2006
PubMed

Insights

The spliceosome complex, crucial for RNA splicing, involves human p14. Researchers determined the structure of human p14 bound to SF3b155, revealing how it interacts with pre-mRNA for accurate splicing.

Area of Science:

  • Molecular Biology
  • Structural Biology
  • RNA Biology

Background:

  • The spliceosome is a large molecular machine responsible for removing introns from precursor mRNAs (pre-mRNAs) in eukaryotes.
  • It is composed of five small nuclear ribonucleoprotein (snRNP) particles.
  • Human p14 is a key component of the U2 and U11/U12 snRNPs within the spliceosome.

Purpose of the Study:

  • To elucidate the structural basis of human p14's interaction with pre-mRNA during spliceosome assembly.
  • To understand the role of p14 in recognizing the branch adenosine of pre-mRNA.

Main Methods:

  • X-ray crystallography was used to determine the 2.5-Å crystal structure of a complex containing human p14 and a peptide from SF3b155.
  • RNA-protein crosslinking experiments were performed on wild-type and mutant p14.
  • Comparative structural analysis and model-building using cryo-EM data were employed.

Main Results:

  • The crystal structure revealed that the RNA recognition motif (RRM) of p14 is largely covered by its C-terminal alpha-helix and the SF3b155 peptide.
  • RNA-protein crosslinking identified a direct interaction between the pre-mRNA branch adenosine and a conserved aromatic residue on the p14.SF3b155 complex.
  • This interaction occurs within a specific pocket on the complex's surface.

Conclusions:

  • The p14.SF3b155 complex presents a noncanonical surface for RNA recognition at a critical step in mammalian spliceosome function.
  • The findings provide structural insights into the mechanism of spliceosome assembly and pre-mRNA binding.

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