6v3d
Cryo-EM structure of the Acinetobacter baumannii Ribosome: 50S subunitCryo-EM structure of the Acinetobacter baumannii Ribosome: 50S subunit
Structural highlights
Function[RL6_ACIB5] This protein binds to the 23S rRNA, and is important in its secondary structure. It is located near the subunit interface in the base of the L7/L12 stalk, and near the tRNA binding site of the peptidyltransferase center. [RL21_ACIB5] This protein binds to 23S rRNA in the presence of protein L20. [RL2_ACIB5] One of the primary rRNA binding proteins. 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 somewhat controversial. Makes several contacts with the 16S rRNA in the 70S ribosome. [A0A009QSN8_9GAMM] The globular domain of the protein is located near the polypeptide exit tunnel on the outside of the subunit, while an extended beta-hairpin is found that lines the wall of the exit tunnel in the center of the 70S ribosome.[HAMAP-Rule:MF_01331] This protein binds specifically to 23S rRNA; its binding is stimulated by other ribosomal proteins, e.g., L4, L17, and L20. It is important during the early stages of 50S assembly. It makes multiple contacts with different domains of the 23S rRNA in the assembled 50S subunit and ribosome.[HAMAP-Rule:MF_01331][RuleBase:RU004008] [RL18_ACIB5] This is one of the proteins that binds and probably mediates the attachment of the 5S RNA into the large ribosomal subunit, where it forms part of the central protuberance. [RL23_ACIB5] One of the early assembly proteins it binds 23S rRNA. One of the proteins that surrounds the polypeptide exit tunnel on the outside of the ribosome. Forms the main docking site for trigger factor binding to the ribosome. [RL13_ACIB5] This protein is one of the early assembly proteins of the 50S ribosomal subunit, although it is not seen to bind rRNA by itself. It is important during the early stages of 50S assembly. [RL16_ACIB5] Binds 23S rRNA and is also seen to make contacts with the A and possibly P site tRNAs. [RL25_ACIB5] This is one of the proteins that binds to the 5S RNA in the ribosome where it forms part of the central protuberance. [RL4_ACIB5] One of the primary rRNA binding proteins, this protein initially binds near the 5'-end of the 23S rRNA. It is important during the early stages of 50S assembly. It makes multiple contacts with different domains of the 23S rRNA in the assembled 50S subunit and ribosome. Forms part of the polypeptide exit tunnel. [RL9_ACIB5] Binds to the 23S rRNA. [N8WQT6_9GAMM] Binds to 23S rRNA. Forms part of two intersubunit bridges in the 70S ribosome.[HAMAP-Rule:MF_01367][RuleBase:RU003950] [RL15_ACIB5] Binds to the 23S rRNA. [V5VGC9_ACIBA] Binds directly to 23S ribosomal RNA and is necessary for the in vitro assembly process of the 50S ribosomal subunit. It is not involved in the protein synthesizing functions of that subunit.[HAMAP-Rule:MF_00382][RuleBase:RU000560] [RL3_ACIB5] One of the primary rRNA binding proteins, it binds directly near the 3'-end of the 23S rRNA, where it nucleates assembly of the 50S subunit. [RL24_ACIB5] One of two assembly initiator proteins, it binds directly to the 5'-end of the 23S rRNA, where it nucleates assembly of the 50S subunit. One of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit. [RL5_ACIB5] This is 1 of the proteins that binds and probably mediates the attachment of the 5S RNA into the large ribosomal subunit, where it forms part of the central protuberance. In the 70S ribosome it contacts protein S13 of the 30S subunit (bridge B1b), connecting the 2 subunits; this bridge is implicated in subunit movement. Contacts the P site tRNA; the 5S rRNA and some of its associated proteins might help stabilize positioning of ribosome-bound tRNAs. [RL19_ACIB5] This protein is located at the 30S-50S ribosomal subunit interface and may play a role in the structure and function of the aminoacyl-tRNA binding site. Publication Abstract from PubMedAntimicrobial resistance is a major health threat as it limits treatment options for infection. At the forefront of this serious issue is Acinetobacter baumannii, a Gram-negative opportunistic pathogen that exhibits the remarkable ability to resist antibiotics through multiple mechanisms. As bacterial ribosomes represent a target for multiple distinct classes of existing antimicrobial agents, we here use single-particle cryo-electron microscopy (cryo-EM) to elucidate five different structural states of the A. baumannii ribosome, including the 70S, 50S, and 30S forms. We also determined interparticle motions of the 70S ribosome in different tRNA bound states using three-dimensional (3D) variability analysis. Together, our structural data further our understanding of the ribosome from A. baumannii and other Gram-negative pathogens and will enable structure-based drug discovery to combat antibiotic-resistant bacterial infections.IMPORTANCE Acinetobacter baumannii is a severe nosocomial threat largely due to its intrinsic antibiotic resistance and remarkable ability to acquire new resistance determinants. The bacterial ribosome serves as a major target for modern antibiotics and the design of new therapeutics. Here, we present cryo-EM structures of the A. baumannii 70S ribosome, revealing several unique species-specific structural features that may facilitate future drug development to combat this recalcitrant bacterial pathogen. Cryo-electron Microscopy Structure of the Acinetobacter baumannii 70S Ribosome and Implications for New Antibiotic Development.,Morgan CE, Huang W, Rudin SD, Taylor DJ, Kirby JE, Bonomo RA, Yu EW mBio. 2020 Jan 21;11(1). pii: mBio.03117-19. doi: 10.1128/mBio.03117-19. PMID:31964740[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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