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Publication Abstract from PubMed

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.

Gut colonization by Bacteroides requires translation by an EF-G paralog lacking GTPase activity.,Han W, Peng BZ, Wang C, Townsend GE 2nd, Barry NA, Peske F, Goodman AL, Liu J, Rodnina MV, Groisman EA EMBO J. 2023 Jan 16;42(2):e112372. doi: 10.15252/embj.2022112372. Epub 2022 Dec , 6. PMID:36472247^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.