Single-molecule study of ribosome hierarchic dynamics at the peptidyl transferase center.
During protein biosynthesis the ribosome moves along mRNA in steps of precisely three nucleotides. The mechanism for this ribosome motion remains elusive. Using a classification algorithm to sort single-molecule fluorescence resonance energy transfer data into subpopulations, we found that the ribosome dynamics detected at the peptidyl transferase center are highly inhomogeneous. The pretranslocation complex has at least four subpopulations that sample two hybrid states, whereas the posttranslocation complex is mainly static. We observed transitions among the ribosome subpopulations under various conditions, including 1), in the presence of EF-G; 2), spontaneously; 3), in different buffers, and 4), bound to antibiotics. Therefore, these subpopulations represent biologically active ribosomes. One key observation indicates that the Hy2 hybrid state only exists in a fluctuating ribosome subpopulation, which prompts us to propose that ribosome dynamics are hierarchically arranged. This proposal may have important implications for the regulation of cellular translation rates.
Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA.
Mediha Esra
ME
Altuntop
Cindy Tu
CT
Ly
Yuhong
Y
Wang
D000465:Algorithms; D055592:Biophysical Phenomena; D031541:Fluorescence Resonance Energy Transfer; D007700:Kinetics; D008958:Models, Molecular; D020653:Peptide Elongation Factor G / Q000378:metabolism; D010458:Peptidyl Transferases / Q000737:chemistry* / Q000378:metabolism*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000737:chemistry / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry* / Q000378:metabolism*; D013816:Thermodynamics
D020653:Peptide Elongation Factor G; D012333:RNA, Messenger; D012269:Ribosomal Proteins; C034661:ribosomal proteins L27; D010458:Peptidyl Transferases