Mutational analysis of two highly conserved UGG sequences of 23 S rRNA from Escherichia coli.
The 23 S-type rRNA contains two phylogenetically conserved UGG sequences, which have the potential to bind the universal CCA-3'-ends of tRNAs at the ribosomal peptidyltransferase center by base pairing. The first two positions, UG, of these sequences at the helix-loop 80 (U2249G2250) and helix-loop 90 (Psi2580G2581) and some related nucleotides were tested by site-directed mutagenesis for their involvement in ribosomal function, i.e. peptidyltransferase. The plasmid-derived mutated 23 S rRNA comprised about 50% of the total 23 S rRNA. None of the single mutations caused an assembly defect, and all 50 S subunits carrying an altered 23 S rRNA could freely exchange with the pools of 70S ribosomes and polysomes. The mutations at the helix-loop 80 region hardly affected bacterial growth. However, mutations at the helix 90 caused severe growth effects and severely impaired the in vitro protein synthesis, showing that this 23 S rRNA region is of high importance for ribosomal function.
Spahn
C M
CM
Max-Planck-Institut für Molekulare Genetik, AG Ribosomen, Ihnestrasse 73, D-14195 Berlin, Germany. nierhaus_kh@mpimg-berlin-dahlem.mpg.de
Remme
J
J
Schäfer
M A
MA
Nierhaus
K H
KH
D001483:Base Sequence; D004252:DNA Mutational Analysis; D004926:Escherichia coli / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D012338:RNA, Ribosomal, 23S / Q000235:genetics*; D012343:RNA, Transfer / Q000378:metabolism; D012360:RNA, Transfer, Phe / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism / Q000648:ultrastructure*; D013329:Structure-Activity Relationship
D012338:RNA, Ribosomal, 23S; D012360:RNA, Transfer, Phe; D012343:RNA, Transfer