7nbu

Structure of the HigB1 toxin mutant K95A from Mycobacterium tuberculosis (Rv1955) and its target, the cspA mRNA, on the E. coli Ribosome.Structure of the HigB1 toxin mutant K95A from Mycobacterium tuberculosis (Rv1955) and its target, the cspA mRNA, on the E. coli Ribosome.

Structural highlights

7nbu is a 10 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 3.11Å
Ligands:	, , , , , , , , , , , , , , , , , , , , , , , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

RL2_ECOLI One of the primary rRNA binding proteins. Located near the base of the L1 stalk, it is probably also mobile. Required for association of the 30S and 50S subunits to form the 70S ribosome, for tRNA binding and peptide bond formation. It has been suggested to have peptidyltransferase activity; this is highly controversial.[HAMAP-Rule:MF_01320_B] In the E.coli 70S ribosome in the initiation state it has been modeled to make several contacts with the 16S rRNA (forming bridge B7b, PubMed:12809609); these contacts are broken in the model with bound EF-G.[HAMAP-Rule:MF_01320_B]

Publication Abstract from PubMed

Toxins of toxin-antitoxin systems use diverse mechanisms to control bacterial growth. Here, we focus on the deleterious toxin of the atypical tripartite toxin-antitoxin-chaperone (TAC) system of Mycobacterium tuberculosis, whose inhibition requires the concerted action of the antitoxin and its dedicated SecB-like chaperone. We show that the TAC toxin is a bona fide ribonuclease and identify exact cleavage sites in mRNA targets on a transcriptome-wide scale in vivo. mRNA cleavage by the toxin occurs after the second nucleotide of the ribosomal A-site codon during translation, with a strong preference for CCA codons in vivo. Finally, we report the cryo-EM structure of the ribosome-bound TAC toxin in the presence of native M. tuberculosis cspA mRNA, revealing the specific mechanism by which the TAC toxin interacts with the ribosome and the tRNA in the P-site to cleave its mRNA target.

Substrate recognition and cryo-EM structure of the ribosome-bound TAC toxin of Mycobacterium tuberculosis.,Mansour M, Giudice E, Xu X, Akarsu H, Bordes P, Guillet V, Bigot DJ, Slama N, D'urso G, Chat S, Redder P, Falquet L, Mourey L, Gillet R, Genevaux P Nat Commun. 2022 May 12;13(1):2641. doi: 10.1038/s41467-022-30373-w. PMID:35552387^[1]

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

References

↑ Mansour M, Giudice E, Xu X, Akarsu H, Bordes P, Guillet V, Bigot DJ, Slama N, D'urso G, Chat S, Redder P, Falquet L, Mourey L, Gillet R, Genevaux P. Substrate recognition and cryo-EM structure of the ribosome-bound TAC toxin of Mycobacterium tuberculosis. Nat Commun. 2022 May 12;13(1):2641. doi: 10.1038/s41467-022-30373-w. PMID:35552387 doi:http://dx.doi.org/10.1038/s41467-022-30373-w

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OCA

[1] Mansour M, Giudice E, Xu X, Akarsu H, Bordes P, Guillet V, Bigot DJ, Slama N, D'urso G, Chat S, Redder P, Falquet L, Mourey L, Gillet R, Genevaux P. Substrate recognition and cryo-EM structure of the ribosome-bound TAC toxin of Mycobacterium tuberculosis. Nat Commun. 2022 May 12;13(1):2641. doi: 10.1038/s41467-022-30373-w. PMID:35552387 doi:http://dx.doi.org/10.1038/s41467-022-30373-w

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