Structures of the Bacterial Ribosome in Classical and Hybrid States of tRNA Binding

Dunkle, Jack A.
Wang, Leyi
Feldman, Michael B.
Pulk, Arto
Chen, Vincent B.
Kapral, Gary J.
Noeske, Jonas
Richardson, Jane S.
Blanchard, Scott C.
Doudna Cate, Jamie H.

¹Departments of Molecular and Cell Biology and Chemistry, University of California at Berkeley, Berkeley, CA 94720, USA. ²Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY 10065, USA. ³Weill Cornell/Rockefeller University/Sloan-Kettering TriInstitutional MD-PhD Program, New York, NY 10065, USA.⁴Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA. ⁵Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
^*Present address: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322. USA. †To whom correspondence should be addressed. E-mail: [email protected]

10 January 2011; accepted 6 April 2011

Science 332(6032):p 981-984, May 20, 2011.

During protein synthesis, the ribosome controls the movement of tRNA and mRNA by means of large-scale structural rearrangements. We describe structures of the intact bacterial ribosome from Escherichia coli that reveal how the ribosome binds tRNA in two functionally distinct states, determined to a resolution of ∽3.2 angstroms by means of x-ray crystallography. One state positions tRNA in the peptidyl-tRNA binding site. The second, a fully rotated state, is stabilized by ribosome recycling factor and binds tRNA in a highly bent conformation in a hybrid peptidyl/exit site. The structures help to explain how the ratchet-like motion of the two ribosomal subunits contributes to the mechanisms of translocation, termination, and ribosome recycling.