6dzk
From Proteopedia
Cryo-EM Structure of Mycobacterium smegmatis C(minus) 30S ribosomal subunit with MPY
Structural highlights
Function[RS11_MYCS2] Located on the platform of the 30S subunit, it bridges several disparate RNA helices of the 16S rRNA. Forms part of the Shine-Dalgarno cleft in the 70S ribosome. [A0QTK6_MYCS2] Required for dimerization of active 70S ribosomes into 100S ribosomes in stationary phase; 100S ribosomes are translationally inactive and sometimes present during exponential growth.[HAMAP-Rule:MF_00839] [RS7_MYCS2] One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the head domain of the 30S subunit. Is located at the subunit interface close to the decoding center, probably blocks exit of the E-site tRNA. [RS19_MYCS2] Protein S19 forms a complex with S13 that binds strongly to the 16S ribosomal RNA.[HAMAP-Rule:MF_00531] [RS14_MYCS2] Binds 16S rRNA, required for the assembly of 30S particles and may also be responsible for determining the conformation of the 16S rRNA at the A site.[HAMAP-Rule:MF_00537] [RS20_MYCS2] Binds directly to 16S ribosomal RNA. [RS13_MYCS2] Located at the top of the head of the 30S subunit, it contacts several helices of the 16S rRNA. In the 70S ribosome it contacts the 23S rRNA (bridge B1a) and protein L5 of the 50S subunit (bridge B1b), connecting the 2 subunits; these bridges are implicated in subunit movement. Contacts the tRNAs in the A and P-sites. [RS17_MYCS2] One of the primary rRNA binding proteins, it binds specifically to the 5'-end of 16S ribosomal RNA. [A0A0D6J3X3_MYCSM] Binds together with S18 to 16S ribosomal RNA.[HAMAP-Rule:MF_00360][SAAS:SAAS00348112] [RS3_MYCS2] Binds the lower part of the 30S subunit head. Binds mRNA in the 70S ribosome, positioning it for translation. [RS12_MYCS2] With S4 and S5 plays an important role in translational accuracy. Interacts with and stabilizes bases of the 16S rRNA that are involved in tRNA selection in the A site and with the mRNA backbone. Located at the interface of the 30S and 50S subunits, it traverses the body of the 30S subunit contacting proteins on the other side and probably holding the rRNA structure together. The combined cluster of proteins S8, S12 and S17 appears to hold together the shoulder and platform of the 30S subunit (By similarity). [RS15_MYCS2] One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it helps nucleate assembly of the platform of the 30S subunit by binding and bridging several RNA helices of the 16S rRNA.[HAMAP-Rule:MF_01343] Forms an intersubunit bridge (bridge B4) with the 23S rRNA of the 50S subunit in the ribosome.[HAMAP-Rule:MF_01343] [RS181_MYCS2] Binds as a heterodimer with protein S6 to the central domain of the 16S rRNA, where it helps stabilize the platform of the 30S subunit.[HAMAP-Rule:MF_00270] [RS8_MYCS2] One of the primary rRNA binding proteins, it binds directly to 16S rRNA central domain where it helps coordinate assembly of the platform of the 30S subunit.[HAMAP-Rule:MF_01302] [RS4_MYCS2] One of the primary rRNA binding proteins, it binds directly to 16S rRNA where it nucleates assembly of the body of the 30S subunit. With S5 and S12 plays an important role in translational accuracy. [RS10_MYCS2] Involved in the binding of tRNA to the ribosomes. [RS5_MYCS2] With S4 and S12 plays an important role in translational accuracy.[HAMAP-Rule:MF_01307] Located at the back of the 30S subunit body where it stabilizes the conformation of the head with respect to the body.[HAMAP-Rule:MF_01307] Publication Abstract from PubMedBacteria respond to zinc starvation by replacing ribosomal proteins that have the zinc-binding CXXC motif (C+) with their zinc-free (C-) paralogues. Consequences of this process beyond zinc homeostasis are unknown. Here, we show that the C- ribosome in Mycobacterium smegmatis is the exclusive target of a bacterial protein Y homolog, referred to as mycobacterial-specific protein Y (MPY), which binds to the decoding region of the 30S subunit, thereby inactivating the ribosome. MPY binding is dependent on another mycobacterial protein, MPY recruitment factor (MRF), which is induced on zinc depletion, and interacts with C- ribosomes. MPY binding confers structural stability to C- ribosomes, promoting survival of growth-arrested cells under zinc-limiting conditions. Binding of MPY also has direct influence on the dynamics of aminoglycoside-binding pockets of the C- ribosome to inhibit binding of these antibiotics. Together, our data suggest that zinc limitation leads to ribosome hibernation and aminoglycoside resistance in mycobacteria. Furthermore, our observation of the expression of the proteins of C- ribosomes in Mycobacterium tuberculosis in a mouse model of infection suggests that ribosome hibernation could be relevant in our understanding of persistence and drug tolerance of the pathogen encountered during chemotherapy of TB. Zinc depletion induces ribosome hibernation in mycobacteria.,Li Y, Sharma MR, Koripella RK, Yang Y, Kaushal PS, Lin Q, Wade JT, Gray TA, Derbyshire KM, Agrawal RK, Ojha AK Proc Natl Acad Sci U S A. 2018 Aug 7;115(32):8191-8196. doi:, 10.1073/pnas.1804555115. Epub 2018 Jul 23. PMID:30038002[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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