Ternary complexes of Escherichia coli aminoacyl-tRNAs with the elongation factor Tu and GTP: thermodynamic and structural studies.
The interaction of 18 different Escherichia coli aminoacyl-tRNA species with elongation factor Tu and GTP has been measured by a fluorescence titration assay under equilibrium conditions. The dissociation constants range from 1.9 +/- 0.2.10(-10) M up to 1020 +/- 250.10(-10) M depending on the nucleotide sequence, secondary structure and the chemical composition of the aminoacyl residue of the particular aminoacyl-tRNA. The 'aminoacyl domain' of tRNA consisting of the single stranded, four-nucleotide-long 3'-terminus, aminoacyl stem of seven base-pairs, T-stem and T-loop contains all elements necessary for binding EF-Tu.GTP. The efficiency of aminoacyl-tRNA interaction with EF-Tu.GTP is modulated by the sequence of this 'aminoacyl domain' and by natural modification of its nucleotide residues. An oligoribonucleotide resembling the aminoacyl stem of E.coli tRNA(Ala) and consisting of a four-membered 3'-end, a stem of seven base-pairs and a loop of six nucleotides was prepared by total chemical synthesis on a polymer support. It can be enzymatically aminoacylated by alanine but does not bind in its aminoacylated form to EF-Tu.GTP.
Laboratorium für Biochemie, Universität Bayreuth, F.R.G.
G
G
Ott
M
M
Schiesswohl
S
S
Kiesewetter
C
C
Förster
L
L
Arnold
V A
VA
Erdmann
M
M
Sprinzl
D000926:Anticodon; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009843:Oligoribonucleotides / Q000138:chemical synthesis / Q000378:metabolism; D010444:Peptide Elongation Factor Tu / Q000378:metabolism*; D012344:RNA, Transfer, Ala / Q000138:chemical synthesis / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D013816:Thermodynamics
D000926:Anticodon; D009843:Oligoribonucleotides; D012344:RNA, Transfer, Ala; D012346:RNA, Transfer, Amino Acyl; D006160:Guanosine Triphosphate; D010444:Peptide Elongation Factor Tu