Simultaneous binding of two proteins to opposite sides of a single transfer RNA.
Transfer RNA (tRNA) is a small nucleic acid (typically 76 nucleotides) that forms binary complexes with proteins, such as aminoacyl tRNA synthetases (RS) and Trbp111. The latter is a widely distributed structure-specific tRNA-binding protein that is incorporated into cell signaling molecules. The structure of Trbp111 was modeled onto to the outer, convex side of the L-shaped tRNA. Here we present RNA footprints that are consistent with this model. This binding mode is in contrast to that of tRNA synthetases, which bind to the inside, or concave side, of tRNA. These opposite locations of binding for these two proteins suggest the possibility of a ternary complex. The formation of a tRNA synthetase--tRNA--Trbp111 ternary complex was detected by two independent methods. The results indicate that the tRNA is sandwiched between the two protein molecules. A thermodynamic and functional analysis is consistent with the tRNA retaining its native structure in the ternary complex. These results may have implications for how the translation apparatus is linked to other cellular machinery.
Nomanbhoy
T
T
The Skaggs Institute for Chemical Biology, The Scripps Research Institute, Beckman Center, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Morales
A J
AJ
Abraham
A T
AT
Vörtler
C S
CS
Giegé
R
R
Schimmel
P
P
D000215:Acylation; D001419:Bacteria / Q000737:chemistry; D001426:Bacterial Proteins; D001665:Binding Sites; D004586:Electrophoresis; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D007533:Isoleucine-tRNA Ligase / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D023282:Nuclease Protection Assays; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011487:Protein Conformation; D015347:RNA Probes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012349:RNA, Transfer, Asp / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012356:RNA, Transfer, Leu / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012358:RNA, Transfer, Met / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D015003:Yeasts / Q000235:genetics
D001426:Bacterial Proteins; D015347:RNA Probes; D012349:RNA, Transfer, Asp; D012356:RNA, Transfer, Leu; D012358:RNA, Transfer, Met; D016601:RNA-Binding Proteins; C120618:Trbp111 protein, Aquifex aeolicus; C024988:tRNA, formylmethionine-; D012343:RNA, Transfer; D007533:Isoleucine-tRNA Ligase