title: RsgA releases RbfA from 30S ribosome during a late stage of ribosome biosynthesis.
abstract: RsgA is a 30S ribosomal subunit-binding GTPase with an unknown function, shortage of which impairs maturation of the 30S subunit. We identified multiple gain-of-function mutants of Escherichia coli rbfA, the gene for a ribosome-binding factor, that suppress defects in growth and maturation of the 30S subunit of an rsgA-null strain. These mutations promote spontaneous release of RbfA from the 30S subunit, indicating that cellular disorders upon depletion of RsgA are due to prolonged retention of RbfA on the 30S subunit. We also found that RsgA enhances release of RbfA from the mature 30S subunit in a GTP-dependent manner but not from a precursor form of the 30S subunit. These findings indicate that the function of RsgA is to release RbfA from the 30S subunit during a late stage of ribosome biosynthesis. This is the first example of the action of a GTPase on the bacterial ribosome assembly described at the molecular level.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan.
authors.forename: Simon
authors.initials: S
authors.lastname: Goto
authors.forename: Shingo
authors.initials: S
authors.lastname: Kato
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Kimura
authors.forename: Akira
authors.initials: A
authors.lastname: Muto
authors.forename: Hyouta
authors.initials: H
authors.lastname: Himeno
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D011485:Protein Binding; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism*; D054680:Ribosome Subunits, Small, Bacterial / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; C092748:RbfA protein, E coli; D012269:Ribosomal Proteins; D020558:GTP Phosphohydrolases; C467318:RsgA protein, E coli