Escherichia coli NusG Links the Lead Ribosome with the Transcription Elongation Complex
Robert S. Washburn,
Philipp K. Zuber,
Ming Sun,
Yaser Hashem,
Bingxin Shen,
Wen Li,
Sho Harvey,
Francisco J. Acosta Reyes,
Max E. Gottesman,
Stefan H. Knauer,
Joachim Frank
Affiliations
Robert S. Washburn
Department of Microbiology & Immunology, Columbia University Medical Center, New York, NY 10032, USA
Philipp K. Zuber
Biochemistry IV - Biopolymers, University of Bayreuth, 95447 Bayreuth, Germany
Ming Sun
Department of Biological Sciences, Columbia University, New York, NY 10027, USA
Yaser Hashem
Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032, USA
Bingxin Shen
Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032, USA
Wen Li
Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032, USA
Sho Harvey
University of Michigan, Ann Arbor, MI 48109, USA
Francisco J. Acosta Reyes
Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032, USA
Max E. Gottesman
Department of Microbiology & Immunology, Columbia University Medical Center, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032, USA; Corresponding author
Stefan H. Knauer
Biochemistry IV - Biopolymers, University of Bayreuth, 95447 Bayreuth, Germany; Corresponding author
Joachim Frank
Department of Biological Sciences, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, NY 10032, USA; Corresponding author
Summary: It has been known for more than 50 years that transcription and translation are physically coupled in bacteria, but whether or not this coupling may be mediated by the two-domain protein N-utilization substance (Nus) G in Escherichia coli is still heavily debated. Here, we combine integrative structural biology and functional analyses to provide conclusive evidence that NusG can physically link transcription with translation by contacting both RNA polymerase and the ribosome. We present a cryo-electron microscopy structure of a NusG:70S ribosome complex and nuclear magnetic resonance spectroscopy data revealing simultaneous binding of NusG to RNAP and the intact 70S ribosome, providing the first direct structural evidence for NusG-mediated coupling. Furthermore, in vivo reporter assays show that recruitment of NusG occurs late in transcription and strongly depends on translation. Thus, our data suggest that coupling occurs initially via direct RNAP:ribosome contacts and is then mediated by NusG.
