Studies on anticodon-anticodon interactions: hemi-protonation of cytosines induces self-pairing through the GCC anticodon of E. coli tRNA-Gly.
The temperature-jump method was used to compare the stability of anticodon-anticodon duplexes formed by the self-association of two tRNAs: yeast tRNA-Asp and Escherichia coli tRNA-Gly. Yeast tRNA-Asp duplexes contain a U/U mismatch while E. coli tRNA-Gly dimers have a C/C mismatch in the middle position of their quasi self-complementary anticodons GUC and GCC, respectively. At neutral pH, it is found that only tRNA-Asp duplexes exist whereas at pH 5.0 only tRNA-Gly duplexes are formed. This reflects the hemiprotonation of the N3 of the cytosines at pH 5.0 which induces a pairing between the two middle residues of the anticodon GCC in E. coli tRNA-Gly. This is the first evidence that a protonated C-C(+) base pair is compatible with the formation of a double helix with antiparallel strands in a natural RNA molecule.
Romby
P
P
Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France.
Westhof
E
E
Moras
D
D
Giegé
R
R
Houssier
C
C
Grosjean
H
H
D000926:Anticodon; D001482:Base Composition; D003596:Cytosine; D004926:Escherichia coli / Q000235:genetics*; D007700:Kinetics; D011522:Protons; D012343:RNA, Transfer; D012345:RNA, Transfer, Amino Acid-Specific; D012353:RNA, Transfer, Gly; D012441:Saccharomyces cerevisiae / Q000235:genetics
D000926:Anticodon; D011522:Protons; D012345:RNA, Transfer, Amino Acid-Specific; D012353:RNA, Transfer, Gly; D003596:Cytosine; D012343:RNA, Transfer