Abstract
We have determined the crystal structure at 2.4 A resolution of a ternary complex between the spliceosomal U2B"/U2A' protein complex and hairpin-loop IV of U2 small nuclear RNA. Unlike its close homologue the U1A protein, U2B" binds to its cognate RNA only in the presence of U2A', which contains leucine-rich repeats in its sequence. The concave surface of a parallel beta-sheet within the leucine-rich-repeat region of U2A' interacts with the ribonucleoprotein domain of U2B" on the surface opposite its RNA-binding surface. The basic carboxy-terminal region of U2A' interacts with the RNA stem. The crystal structure reveals how protein-protein interaction regulates RNA-binding specificity, and how replacing only a few key residues allows the U2B" and U1A proteins to discriminate between their cognate RNA hairpins by forming alternative networks of interactions.
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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Animals
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Autoantigens
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Crystallography, X-Ray
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Drosophila
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Drosophila Proteins*
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Evolution, Molecular
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Humans
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Leucine-Rich Repeat Proteins
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Models, Molecular
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Molecular Sequence Data
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Nucleic Acid Conformation
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Protein Binding
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Protein Conformation
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Proteins / chemistry
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RNA, Small Nuclear / chemistry*
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RNA, Small Nuclear / metabolism
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RNA-Binding Proteins*
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Recombinant Proteins / chemistry
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Ribonucleoprotein, U1 Small Nuclear / chemistry
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Ribonucleoprotein, U2 Small Nuclear / chemistry*
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Ribonucleoprotein, U2 Small Nuclear / metabolism
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Ribonucleoproteins, Small Nuclear
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snRNP Core Proteins
Substances
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Autoantigens
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Drosophila Proteins
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Leucine-Rich Repeat Proteins
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Proteins
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RNA, Small Nuclear
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RNA-Binding Proteins
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Recombinant Proteins
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Ribonucleoprotein, U1 Small Nuclear
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Ribonucleoprotein, U2 Small Nuclear
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Ribonucleoproteins, Small Nuclear
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SNRPB2 protein, human
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U2A protein, Drosophila
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U2A' protein, human
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snRNP Core Proteins
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snf protein, Drosophila