Structural Basis for Polypyrimidine Tract Recognition by the Essential Pre-mRNA Splicing Factor U2AF65
The essential pre-mRNA splicing factor, U2AF{sup 65}, guides the early stages of splice site choice by recognizing a polypyrimidine (Py)-tract consensus sequence near the 3'-splice site. Since Py-tracts are relatively poorly conserved in higher eukaryotes, U2AF{sup 65} is faced with the problem of specifying uridine-rich sequences, yet tolerating a variety of nucleotide substitutions found in natural Py-tracts. To better understand these apparently contradictory RNA binding characteristics, the X-ray structure of the U2AF{sup 65} RNA binding domain bound to a Py-tract composed of seven uridines has been determined at 2.5Angstroms resolution. Specific hydrogen bonds between U2AF{sup 65} and the uracil bases provide an explanation for polyuridine recognition. Flexible sidechains and bound water molecules form the majority of the base contacts, and potentially could rearrange when the U2AF{sup 65} structure adapts to different Py-tract sequences. The energetic importance of conserved residues for Py-tract binding is established by analysis of site-directed mutant U2AF{sup 65} proteins using surface plasmon resonance.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 914077
- Report Number(s):
- BNL-78645-2007-JA; TRN: US0801524
- Journal Information:
- Mol. Cell, Vol. 23, Issue 1
- Country of Publication:
- United States
- Language:
- English
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