Abstract
We have determined the crystal structure of a spliceosomal RNP complex comprising the 15.5kD protein of the human U4/U6.U5 tri-snRNP and the 5' stem-loop of U4 snRNA. The protein interacts almost exclusively with a purine-rich (5+2) internal loop within the 5' stem-loop, giving an unusual RNA fold characterized by two tandem sheared G-A base pairs, a high degree of purine stacking, and the accommodation of a single RNA base, rotated out of the RNA chain, in a pocket of the protein. Apart from yielding the structure of an important entity in the pre-mRNA splicing apparatus, this work also implies a model for the complex of the 15.5kD protein with box C/D snoRNAs. It additionally suggests a general recognition principle in a novel family of RNA binding proteins.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Base Pairing
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Base Sequence
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Crystallography, X-Ray
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Humans
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Models, Molecular
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Molecular Sequence Data
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Molecular Weight
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Nucleic Acid Conformation
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Protein Conformation
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Purines / metabolism
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RNA Precursors / chemistry
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RNA Precursors / genetics
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RNA Precursors / metabolism
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RNA, Small Nuclear / chemistry
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RNA, Small Nuclear / genetics
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RNA, Small Nuclear / metabolism*
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RNA-Binding Proteins / chemistry
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RNA-Binding Proteins / metabolism
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Ribonucleoproteins, Small Nuclear / chemistry*
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Ribonucleoproteins, Small Nuclear / metabolism*
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Ribonucleoproteins, Small Nucleolar / chemistry
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Sequence Alignment
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Spliceosomes / chemistry*
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Spliceosomes / genetics
Substances
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Purines
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RNA Precursors
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RNA, Small Nuclear
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RNA-Binding Proteins
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Ribonucleoproteins, Small Nuclear
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Ribonucleoproteins, Small Nucleolar
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U4 small nuclear RNA