Abstract
Within the large domain of the human signal recognition particle (SRP), 18 mutant SRP RNAs were constructed to disrupt Watson-Crick and G-U basepairs in helices 5, 6 and 8. Using a double-filter assay, the competitive binding of the mutant RNAs to purified human SRP68/72 or to a 7.4 kDa RNA-binding fragment of SRP72 (72frg) was measured. Binding of SRP68/72 was impaired by several mutations in the large domain with the most pronounced effects caused by changes in helix 5 (residues 222-231) and helix 8 (residues 176-191 and 202-214). Binding of the 72frg was diminished prominently by altering helix 5, in particular residues 120-128, and was unaffected by deleting helices 6 and 8. Deleting helix 8 diminished binding of SRP68/72 to a greater extent than deleting helix 6. The data suggest that nucleotide residues throughout most of the large SRP domain are directly and/or indirectly engaged in the binding of SRP68. In contrast, SRP72 binds only to a portion of the 5ef region.
Original language | English (US) |
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Pages (from-to) | 154-159 |
Number of pages | 6 |
Journal | RNA biology |
Volume | 4 |
Issue number | 3 |
DOIs | |
State | Published - 2007 |
Keywords
- Protein targeting
- Protein-RNA interactions
- RNP assembly
- SRP
- Signal recognition particle
- Site-directed mutagenesis
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology