Cryo-EM structure of the ribosome-bound Bacteroides thetaiotaomicron EF-G2

Experimental Data Snapshot

  • Resolution: 4.00 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

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Gut colonization by Bacteroides requires translation by an EF-G paralog lacking GTPase activity.

Han, W.Peng, B.Z.Wang, C.Townsend 2nd, G.E.Barry, N.A.Peske, F.Goodman, A.L.Liu, J.Rodnina, M.V.Groisman, E.A.

(2022) EMBO J : e112372-e112372

  • DOI: https://doi.org/10.15252/embj.2022112372
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Protein synthesis is crucial for cell growth and survival yet one of the most energy-consuming cellular processes. How, then, do cells sustain protein synthesis under starvation conditions when energy is limited? To accelerate the translocation of mRNA-tRNAs through the ribosome, bacterial elongation factor G (EF-G) hydrolyzes energy-rich guanosine triphosphate (GTP) for every amino acid incorporated into a protein. Here, we identify an EF-G paralog-EF-G2-that supports translocation without hydrolyzing GTP in the gut commensal bacterium Bacteroides thetaiotaomicron. EF-G2's singular ability to sustain protein synthesis, albeit at slow rates, is crucial for bacterial gut colonization. EF-G2 is ~10-fold more abundant than canonical EF-G1 in bacteria harvested from murine ceca and, unlike EF-G1, specifically accumulates during carbon starvation. Moreover, we uncover a 26-residue region unique to EF-G2 that is essential for protein synthesis, EF-G2 dissociation from the ribosome, and responsible for the absence of GTPase activity. Our findings reveal how cells curb energy consumption while maintaining protein synthesis to advance fitness in nutrient-fluctuating environments.

  • Organizational Affiliation

    Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Tetracycline resistance protein TetQ718Bacteroides thetaiotaomicron VPI-5482Mutation(s): 0 
Gene Names: BT_2167
Find proteins for Q8A5S1 (Bacteroides thetaiotaomicron (strain ATCC 29148 / DSM 2079 / JCM 5827 / CCUG 10774 / NCTC 10582 / VPI-5482 / E50))
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Go to UniProtKB:  Q8A5S1
Entity Groups  
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UniProt GroupQ8A5S1
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 4.00 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United States--

Revision History  (Full details and data files)

  • Version 1.0: 2023-01-04
    Type: Initial release