National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)
P01AI095208
米国
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)
U24GM116787
米国
引用
ジャーナル: Nat Commun / 年: 2022 タイトル: Interplay between an ATP-binding cassette F protein and the ribosome from Mycobacterium tuberculosis. 著者: Zhicheng Cui / Xiaojun Li / Joonyoung Shin / Howard Gamper / Ya-Ming Hou / James C Sacchettini / Junjie Zhang / 要旨: EttA, energy-dependent translational throttle A, is a ribosomal factor that gates ribosome entry into the translation elongation cycle. A detailed understanding of its mechanism of action is limited ...EttA, energy-dependent translational throttle A, is a ribosomal factor that gates ribosome entry into the translation elongation cycle. A detailed understanding of its mechanism of action is limited due to the lack of high-resolution structures along its ATPase cycle. Here we present the cryo-electron microscopy (cryo-EM) structures of EttA from Mycobacterium tuberculosis (Mtb), referred to as MtbEttA, in complex with the Mtb 70S ribosome initiation complex (70SIC) at the pre-hydrolysis (ADPNP) and transition (ADP-VO) states, and the crystal structure of MtbEttA alone in the post-hydrolysis (ADP) state. We observe that MtbEttA binds the E-site of the Mtb 70SIC, remodeling the P-site tRNA and the ribosomal intersubunit bridge B7a during the ribosomal ratcheting. In return, the rotation of the 30S causes conformational changes in MtbEttA, forcing the two nucleotide-binding sites (NBSs) to alternate to engage each ADPNP in the pre-hydrolysis states, followed by complete engagements of both ADP-VO molecules in the ATP-hydrolysis transition states. In the post-hydrolysis state, the conserved ATP-hydrolysis motifs of MtbEttA dissociate from both ADP molecules, leaving two nucleotide-binding domains (NBDs) in an open conformation. These structures reveal a dynamic interplay between MtbEttA and the Mtb ribosome, providing insights into the mechanism of translational regulation by EttA-like proteins.