Structural highlights
Function
[C9QXP2_ECOD1] 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 (By similarity).[HAMAP-Rule:MF_01366] [C9QTZ1_ECOD1] 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 (By similarity).[RuleBase:RU000560][HAMAP-Rule:MF_00382] [C9QXG9_ECOD1] Binds 23S rRNA and is also seen to make contacts with the A and possibly P site tRNAs.[HAMAP-Rule:MF_01342] [C9QXH3_ECOD1] One of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit (By similarity).[HAMAP-Rule:MF_01326] 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 (By similarity).[HAMAP-Rule:MF_01326] [C9QRC1_ECOD1] This is one of the proteins that binds to the 5S RNA in the ribosome where it forms part of the central protuberance.[HAMAP-Rule:MF_01336][SAAS:SAAS00023223] [C9QTM2_ECOD1] Binds to the 23S rRNA.[HAMAP-Rule:MF_00503] [H0QFK1_ECOLI] Binds directly to 23S rRNA. The L1 stalk is quite mobile in the ribosome, and is involved in E site tRNA release.[HAMAP-Rule:MF_01318] Protein L1 is also a translational repressor protein, it controls the translation of the L11 operon by binding to its mRNA.[HAMAP-Rule:MF_01318] [C9QXG7_ECOD1] 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 (By similarity).[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 (By similarity).[RuleBase:RU004008][HAMAP-Rule:MF_01331] [C9QXH7_ECOD1] 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.[HAMAP-Rule:MF_01365][RuleBase:RU003870] [C9QXG5_ECOD1] 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.[HAMAP-Rule:MF_01320] [C9QXH4_ECOD1] 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.[HAMAP-Rule:MF_01333] [C9QXH8_ECOD1] 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.[HAMAP-Rule:MF_01337] [C9QY61_ECOD1] This protein binds to 23S rRNA in the presence of protein L20.[HAMAP-Rule:MF_01363][RuleBase:RU000562][SAAS:SAAS00030247] [C9QXG2_ECOD1] 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.[HAMAP-Rule:MF_01325] [B1X6G9_ECODH] 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.[HAMAP-Rule:MF_01369] [C9QXG3_ECOD1] Forms part of the polypeptide exit tunnel (By similarity).[HAMAP-Rule:MF_01328] 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 (By similarity).[HAMAP-Rule:MF_01328] [C9QXH2_ECOD1] Binds to 23S rRNA. Forms part of two intersubunit bridges in the 70S ribosome.[HAMAP-Rule:MF_01367][RuleBase:RU003950] [C9R119_ECOD1] 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.[HAMAP-Rule:MF_00402][RuleBase:RU000559] [C9QPR2_ECOD1] GTPase that plays an essential role in the late steps of ribosome biogenesis.[HAMAP-Rule:MF_00195][RuleBase:RU004481] [C9QV94_ECOD1] This protein binds directly to 23S ribosomal RNA (By similarity).[HAMAP-Rule:MF_00736][RuleBase:RU003979][SAAS:SAAS020785_004_002551] [RL15_ECOLI] This protein binds the 5S rRNA. It is required for the late stages of subunit assembly, and is essential for 5S rRNA assembly onto the ribosome.[HAMAP-Rule:MF_01341_B]
Publication Abstract from PubMed
Many ribosome-interacting GTPases, with proposed functions in ribosome biogenesis, are also implicated in the cellular regulatory coupling between ribosome assembly process and various growth control pathways. EngA is an essential GTPase in bacteria, and intriguingly, it contains two consecutive GTPase domains (GD), being one-of-a-kind among all known GTPases. EngA is required for the 50S subunit maturation. However, its molecular role remains elusive. Here, we present the structure of EngA bound to the 50S subunit. Our data show that EngA binds to the peptidyl transferase center (PTC) and induces dramatic conformational changes on the 50S subunit, which virtually returns the 50S subunit to a state similar to that of the late-stage 50S assembly intermediates. Very interestingly, our data show that the two GDs exhibit a pseudo-two-fold symmetry in the 50S-bound conformation. Our results indicate that EngA recognizes certain forms of the 50S assembly intermediates, and likely facilitates the conformational maturation of the PTC of the 23S rRNA in a direct manner. Furthermore, in a broad context, our data also suggest that EngA might be a sensor of the cellular GTP/GDP ratio, endowed with multiple conformational states, in response to fluctuations in cellular nucleotide pool, to facilitate and regulate ribosome assembly.
Structural insights into the function of a unique tandem GTPase EngA in bacterial ribosome assembly.,Zhang X, Yan K, Zhang Y, Li N, Ma C, Li Z, Zhang Y, Feng B, Liu J, Sun Y, Xu Y, Lei J, Gao N Nucleic Acids Res. 2014 Nov 11. pii: gku1135. PMID:25389271[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Zhang X, Yan K, Zhang Y, Li N, Ma C, Li Z, Zhang Y, Feng B, Liu J, Sun Y, Xu Y, Lei J, Gao N. Structural insights into the function of a unique tandem GTPase EngA in bacterial ribosome assembly. Nucleic Acids Res. 2014 Nov 11. pii: gku1135. PMID:25389271 doi:http://dx.doi.org/10.1093/nar/gku1135
