8DMF

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

Summary for 8DMF

• Entry DOI: 10.2210/pdb8dmf/pdb
• EMDB information: 27535 27543 27546 27547
• Descriptor: Tetracycline resistance protein TetQ, MAGNESIUM ION, GUANOSINE-5'-TRIPHOSPHATE (3 entities in total)
• Functional Keywords: translation elongation factor, bacteroides thetaiotaomicron ef-g2, translation
• Biological source: Bacteroides thetaiotaomicron VPI-5482
• Total number of polymer chains: 1
• Total formula weight: 80901.34

Authors

Wang, C.,Han, W.,Groisman, E.A.,Liu, J. (deposition date: 2022-07-08, release date: 2023-01-04, Last modification date: 2024-06-12)

Primary citation

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.
Gut colonization by Bacteroides requires translation by an EF-G paralog lacking GTPase activity.
Embo J., :e112372-e112372, 2022

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.

PubMed: 36472247
DOI: 10.15252/embj.2022112372

Experimental method

ELECTRON MICROSCOPY (4 Å)