title: Ribosome-small-subunit-dependent GTPase interacts with tRNA-binding sites on the ribosome.
abstract: RsgA (ribosome-small-subunit-dependent GTPase A, also known as YjeQ) is a unique GTPase in that guanosine triphosphate hydrolytic activity is activated by the small subunit of the ribosome. Disruption of the gene for RsgA from the genome affects the growth of cells, the subunit association of the ribosome, and the maturation of 16S rRNA. To study the interaction of Escherichia coli RsgA with the ribosome, chemical modifications using dimethylsulfate and kethoxal were performed on the small subunit in the presence or in the absence of RsgA. The chemical reactivities at G530, A790, G925, G926, G966, C1054, G1339, G1405, A1413, and A1493 in 16S rRNA were reduced, while those at A532, A923, G1392, A1408, A1468, and A1483 were enhanced, by the addition of RsgA, together with 5'-guanylylimidodiphosphate. Among them, the chemical reactivities at A532, A790, A923, G925, G926, C1054, G1392, A1413, A1468, A1483, and A1493 were not changed when RsgA was added together with GDP. These results indicate that the binding of RsgA induces conformational changes around the A site, P site, and helix 44, and that guanosine triphosphate hydrolysis induces partial conformational restoration, especially in the head, to dissociate RsgA from the small subunit. RsgA has the capacity to coexist with mRNA in the ribosome while it promotes dissociation of tRNA from the ribosome.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori 036-8561, Japan.
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Kimura
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Takagi
authors.forename: Yuya
authors.initials: Y
authors.lastname: Hirata
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Hase
authors.forename: Akira
authors.initials: A
authors.lastname: Muto
authors.forename: Hyouta
authors.initials: H
authors.lastname: Himeno
mesh_terms: D000447:Aldehydes / Q000494:pharmacology; D001665:Binding Sites; D002074:Butanones; D029968:Escherichia coli Proteins / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006921:Hygromycin B / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism*; D054657:Ribosome Subunits / Q000378:metabolism*; D013463:Sulfuric Acid Esters / Q000494:pharmacology
chemical_list: D000447:Aldehydes; D002074:Butanones; D029968:Escherichia coli Proteins; C503923:GDPNP compound; D012333:RNA, Messenger; D013463:Sulfuric Acid Esters; D006921:Hygromycin B; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; C005135:kethoxal; D020558:GTP Phosphohydrolases; C467318:RsgA protein, E coli; C007482:dimethyl sulfate