PMID:16324148

Citation	Ueta, M, Yoshida, H, Wada, C, Baba, T, Mori, H and Wada, A (2005) Ribosome binding proteins YhbH and YfiA have opposite functions during 100S formation in the stationary phase of Escherichia coli. Genes Cells 10:1103-12
Abstract	During the stationary phase of Escherichia coli growth, ribosomal structure changes drastically. Proteins RMF, YhbH, YfiA and SRA are expressed and bind to ribosome particles. In a process named 'ribosomal hibernation,' RMF binding induces the dimerization and subsequent inactivation of 70S ribosomes. Here, we examined the functions of YhbH and YfiA in the formation of 70S dimers using deletion mutants of YhbH and YfiA. The yfiA deletion mutant expressed YhbH and RMF in the stationary phase and formed a greater number of 100S particles than the wild-type, showing that YhbH promotes and stabilizes 100S formation. In contrast, the yhbH deletion mutant expressed YfiA and RMF and produced no 70S dimers, suggesting that YfiA prevents 70S dimer formation. Thus, YhbH and YfiA have opposite functions in 70S dimer formation. YhbH and YfiA share 40% sequence homology, suggesting that their binding sites overlap and they compete for a region proximal to the P- and A-sites on 30S subunits. In the yhbH and yfiA double deletion mutant, which expresses only RMF, 70S dimers were observed as 90S particles. Since 100S particles were seen in the yfiA deletion mutant containing RMF and YhbH, YhbH probably converts immature 90S ribosomes into mature 100S particles.
Links	PubMed Online version:10.1111/j.1365-2443.2005.00903.x
Keywords	Amino Acid Sequence; Binding Sites/genetics; Binding Sites/physiology; Cell Fractionation; Electrophoresis, Gel, Two-Dimensional; Escherichia coli/growth & development; Escherichia coli/physiology; Escherichia coli Proteins/genetics; Escherichia coli Proteins/pharmacology; Escherichia coli Proteins/physiology; Gene Expression Regulation, Bacterial; Microbial Viability/genetics; Models, Biological; Molecular Sequence Data; Mutation; Protein Binding/physiology; Ribosomal Proteins/genetics; Ribosomal Proteins/pharmacology; Ribosomal Proteins/physiology; Ribosomes/drug effects; Ribosomes/metabolism; Ribosomes/physiology; Sequence Homology
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ECOLI:RP5M		GO:0031118: rRNA pseudouridine synthesis	ECO:0000315:		P		Figure 2. YhbH converts immature 90S particles to mature 100S ribosomal particles by promoting both particle formation and stabilization.	complete

References

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