Functional analysis of the invariant residue G791 of Escherichia coli 16S rRNA.
The nucleotide at position 791(G791) of E. coli 16S rRNA was previously identified as an invariant residue for ribosomal function. In order to characterize the functional role of G791, base substitutions were introduced at this position, and mutant ribosomes were analyzed with regard to their protein synthesis ability, via the use of a specialized ribosome system. These ribosomal RNA mutations attenuated the ability of ribosomes to conduct protein synthesis by more than 65%. A transition mutation (G to A) exerted a moderate effect on ribosomal function, whereas a transversion mutation (G to C or U) resulted in a loss of protein synthesis ability of more than 90%. The sucrose gradient profiles of ribosomes and primer extension analysis showed that the loss of protein-synthesis ability of mutant ribosomes harboring a base substitution from G to U at position 791 stems partially from its inability to form 70S ribosomes. These findings show the involvement of the nucleotide at position 791 in the association of ribosomal subunits and protein synthesis steps after 70S formation, as well as the possibility of using 16S rRNA mutated at position 791 for the selection of second-site revertants in order to identify ligands that interact with G791 in protein synthesis.
Song
Woo-Seok
WS
Department of Life Science, Chung-Ang University, Seoul, Republic of Korea.
Kim
Hong-Man
HM
Kim
Jae-Hong
JH
Sim
Se-Hoon
SH
Ryou
Sang-Mi
SM
Kim
Sanggoo
S
Cha
Chang-Jun
CJ
Cunningham
Philip R
PR
Bae
Jeehyeon
J
Lee
Kangseok
K
D001483:Base Sequence; D017931:DNA Primers; D004926:Escherichia coli / Q000235:genetics*; D014644:Genetic Variation; D006147:Guanine; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D020641:Polymorphism, Single Nucleotide; D012329:RNA, Bacterial / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000235:genetics*
D017931:DNA Primers; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D006147:Guanine