2g4b
From Proteopedia
Structure of U2AF65 variant with polyuridine tract
Structural highlights
Function[U2AF2_HUMAN] Necessary for the splicing of pre-mRNA. Induces cardiac troponin-T (TNNT2) pre-mRNA exon inclusion in muscle. Regulates the TNNT2 exon 5 inclusion through competition with MBNL1. Binds preferentially to a single-stranded structure within the polypyrimidine tract of TNNT2 intron 4 during spliceosome assembly. Required for the export of mRNA out of the nucleus, even if the mRNA is encoded by an intron-less gene. Represses the splicing of MAPT/Tau exon 10.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe essential pre-mRNA splicing factor, U2AF(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(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(65) RNA binding domain bound to a Py tract composed of seven uridines has been determined at 2.5 A resolution. Specific hydrogen bonds between U2AF(65) and the uracil bases provide an explanation for polyuridine recognition. Flexible side chains and bound water molecules form the majority of the base contacts and potentially could rearrange when the U2AF(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(65) proteins using surface plasmon resonance. Structural basis for polypyrimidine tract recognition by the essential pre-mRNA splicing factor U2AF65.,Sickmier EA, Frato KE, Shen H, Paranawithana SR, Green MR, Kielkopf CL Mol Cell. 2006 Jul 7;23(1):49-59. PMID:16818232[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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