Abstract
All organisms incorporate post-transcriptional modifications into ribosomal RNA, influencing ribosome assembly and function in ways that are poorly understood. The most highly conserved modification is the dimethylation of two adenosines near the 3' end of the small subunit rRNA. Lack of these methylations due to deficiency in the KsgA methyltransferase stimulates translational errors during both the initiation and elongation phases of protein synthesis and confers resistance to the antibiotic kasugamycin. Here, we present the X-ray crystal structure of the Thermus thermophilus 30S ribosomal subunit lacking these dimethylations. Our data indicate that the KsgA-directed methylations facilitate structural rearrangements in order to establish a functionally optimum subunit conformation during the final stages of ribosome assembly.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Base Sequence
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Crystallography, X-Ray
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Methylation
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Methyltransferases / genetics
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Methyltransferases / metabolism*
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Models, Molecular
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Molecular Sequence Data
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Mutant Proteins / chemistry
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Mutant Proteins / genetics
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Mutant Proteins / metabolism
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Nucleic Acid Conformation
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Protein Conformation
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RNA, Ribosomal, 16S / chemistry
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RNA, Ribosomal, 16S / metabolism*
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RNA, Ribosomal, 16S / physiology
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Ribosome Subunits, Small, Bacterial / chemistry*
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Ribosome Subunits, Small, Bacterial / metabolism
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Ribosome Subunits, Small, Bacterial / physiology
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Ribosomes / chemistry
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Ribosomes / metabolism
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Ribosomes / physiology*
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Structure-Activity Relationship
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Thermus thermophilus / chemistry
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Thermus thermophilus / metabolism
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Thermus thermophilus / physiology
Substances
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Mutant Proteins
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RNA, Ribosomal, 16S
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Methyltransferases
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16S rRNA (adenine(1518)-N(6)-adenine(1519)-N(6))-dimethyltransferase