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Crystal Structure of ERA in Complex with MgGNP and the 3' End of 16S rRNA
Structural highlights
FunctionERA_AQUAE An essential GTPase that binds both GDP and GTP, with rapid nucleotide exchange. Plays a role in 16S rRNA processing and 30S ribosomal subunit biogenesis and possibly also in cell cycle regulation and energy metabolism (By similarity). The GTPase is stimulated about 6-fold in the presence of a 12 nucleotide 16S rRNA C-terminal fragment. Mutations in the rRNA sequence obviate stimulation. RNA-binding depends on GTP-binding by the GTPase domain. May function as a checkpoint for assembly of the 30S ribosomal subunit. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedERA, composed of an N-terminal GTPase domain followed by an RNA-binding KH domain, is essential for bacterial cell viability. It binds to 16S rRNA and the 30S ribosomal subunit. However, its RNA-binding site, the functional relationship between the two domains, and its role in ribosome biogenesis remain unclear. We have determined two crystal structures of ERA, a binary complex with GDP and a ternary complex with a GTP-analog and the 1531AUCACCUCCUUA1542 sequence at the 3' end of 16S rRNA. In the ternary complex, the first nine of the 12 nucleotides are recognized by the protein. We show that GTP binding is a prerequisite for RNA recognition by ERA and that RNA recognition stimulates its GTP-hydrolyzing activity. Based on these and other data, we propose a functional cycle of ERA, suggesting that the protein serves as a chaperone for processing and maturation of 16S rRNA and a checkpoint for assembly of the 30S ribosomal subunit. The AUCA sequence is highly conserved among bacteria, archaea, and eukaryotes, whereas the CCUCC, known as the anti-Shine-Dalgarno sequence, is conserved in noneukaryotes only. Therefore, these data suggest a common mechanism for a highly conserved ERA function in all three kingdoms of life by recognizing the AUCA, with a "twist" for noneukaryotic ERA proteins by also recognizing the CCUCC. Structure of ERA in complex with the 3' end of 16S rRNA: implications for ribosome biogenesis.,Tu C, Zhou X, Tropea JE, Austin BP, Waugh DS, Court DL, Ji X Proc Natl Acad Sci U S A. 2009 Sep 1;106(35):14843-8. Epub 2009 Aug 17. PMID:19706445[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences | ||||||||||||||||||||
