2n8n | pdb_00002n8n
Solution structure of translation initiation factor
Structural highlights
Function[IF1_STAAM] One of the essential components for the initiation of protein synthesis. Stabilizes the binding of IF-2 and IF-3 on the 30S subunit to which N-formylmethionyl-tRNA(fMet) subsequently binds. Helps modulate mRNA selection, yielding the 30S pre-initiation complex (PIC). Upon addition of the 50S ribosomal subunit IF-1, IF-2 and IF-3 are released leaving the mature 70S translation initation complex. Publication Abstract from PubMedTranslation initiation, the rate-limiting step in the protein synthesis, is tightly regulated. As one of the translation initiation factors, translation initiation factor 1 (IF1) plays crucial roles not only in translation but also in many cellular processes that are important for genomic stability, such as the activity of RNA chaperones. Here, we characterize the RNA interactions and dynamics of IF1 from Staphylococcus aureus Mu50 (IF1Sa) by NMR spectroscopy. First, the NMR-derived solution structure of IF1Sa revealed that IF1Sa adopts an oligonucleotide/oligosaccharide binding (OB)-fold. Structural comparisons showed large deviations in the alpha-helix and the following loop, which are potential RNA-binding regions of the OB-fold, as well as differences in the electrostatic potential surface among bacterial IF1s. Second, the 15N NMR relaxation data for IF1Sa indicated the flexible nature of the alpha-helix and the following loop region of IF1Sa. Third, RNA-binding properties were studied using FP assays and NMR titrations. FP binding assays revealed that IF1Sa binds to RNAs with moderate affinity. In combination with the structural analysis, the NMR titration results revealed the RNA binding sites. Taken together, these results show that IF1Sa binds RNAs with moderate binding affinity via the residues that occupy the large surface area of its beta-barrel. These findings suggest that IF1Sa is likely to bind RNA in various conformations rather than only at a specific site and indicate that the flexible RNA binding mode of IF1Sa is necessary for its interaction with various RNA substrates. Structure and dynamics study of translation initiation factor 1 from Staphylococcus aureus suggests its RNA binding mode.,Kim DH, Kang SJ, Lee KY, Jang SB, Kang SM, Lee BJ Biochim Biophys Acta. 2017 Jan;1865(1):65-75. doi: 10.1016/j.bbapap.2016.10.009. , Epub 2016 Oct 23. PMID:27784646[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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