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Literature summary for 3.6.5.3 extracted from
- Human eIF5 and eIF1A compete for binding to eIF5B (2018), Biochemistry, 57, 5910-5920 .
Activating Compound
| Activating Compound | Comment | Organism | Structure |
|---|---|---|---|
| eIF1A | GTPase-activating protein (GAP) for eIF2, the interaction is mediated by an eIF5B-binding motif located at the C-terminus of eIF1A. The C-terminal tail of eIF1A is located in the ribosomal P-site and counteracts the transition from open to closed complex. EIF5 competes with eIF1A for binding to eIF5B | Homo sapiens | |
| eIF5 | eIF5 is the GTPase-activating protein (GAP) of eIF2, eIF5 promotes GTP hydrolysis by eIF2, followed by phosphate release. EIF2-GDP has lower affinity for Met-tRNAi than eIF2-GTP, and is released together with its GAP, eIF5 | Homo sapiens | |
| eIF5 | human eIF5, the GTPase-activating protein (GAP) for eIF2, also binds to eIF5B, with affinity that is about two orders of magnitude higher than that of eIF1A. The interaction is mediated by an eIF5B-binding motif located at the C-terminus of eIF5, similar to that of eIF1A and the two proteins compete for binding to eIF5B. NMR structure analysis of the binding interface between eIF5-CT39 and eIF5B-D4, structure of the human eIF5B-D4-eIF5-C-terminal tail (CTT) complex, overview | Homo sapiens | |
| additional information | evolutionary conservation of the eIF5B-binding motif in eIF1A and eIF5 | Homo sapiens |
Cloned(Commentary)
| Cloned (Comment) | Organism |
|---|---|
| recombinant expression of wild-type eIF5B and truncated mutants eIF5B587-1220 (GH-DELTAeIF5B), eIF5B951-1220 comprising domains 3 and 4 (GH-eIF5B-D34), and eIF5B1076-1220 comprising domain 4 (GH-eIF5B-D4), all with an N-terminal GB1 tag, His6-tag, and a TEV protease cleavage site (GH-tag) | Homo sapiens |
Localization
| Localization | Comment | Organism | GeneOntology No. | Textmining |
|---|---|---|---|---|
| ribosome | - |
Homo sapiens | 5840 | - |
Metals/Ions
| Metals/Ions | Comment | Organism | Structure |
|---|---|---|---|
| Mg2+ | required | Homo sapiens |  |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| GTP + H2O | Homo sapiens | - |
GDP + phosphate | - |
? | |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Homo sapiens | O60841 | - |
- |
| Homo sapiens | P05198 AND P20042 AND P41091 | subunits EIF2S1, EIF2S2 and EIF2S3 or eIF-2-alpha, eIF-2-beta, and eIF-2-gamma, respectively | - |
Purification (Commentary)
| Purification (Comment) | Organism |
|---|---|
| recombinant GB1-His6-tagged wild-type eIF5B and truncated mutants eIF5B587-1220 (GH-DELTAeIF5B), eIF5B951-1220 comprising domains 3 and 4 (GH-eIF5B-D34), and eIF5B1076-1220 comprising domain 4 (GH-eIF5B-D4) by nickel affinity chromatography, tag cleavage by TEV protease, and anion exchange chromatography to remove the GB1 tag | Homo sapiens |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| GTP + H2O | - |
Homo sapiens | GDP + phosphate | - |
? | |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| eIF2 | - |
Homo sapiens |
| eIF5B | - |
Homo sapiens |
| eukaryotic translation initiation factor 2 | - |
Homo sapiens |
| eukaryotic translation initiation factor 5B | - |
Homo sapiens |
General Information
| General Information | Comment | Organism |
|---|---|---|
| metabolism | in human, eIF5B displacing eIF2 from Met-tRNAi upon subunit joining may be coupled to eIF1A displacing eIF5 from eIF5B, allowing the eIF5:eIF2-GDP complex to leave the ribosome | Homo sapiens |
| additional information | human eIF5 competes with eIF1A for binding and has about 100fold higher affinity for eIF5B | Homo sapiens |
| physiological function | eukaryotic translation initiation is a multistep process requiring a number of eukaryotic translation initiation factors (eIFs). Two GTPases play key roles in the process. EIF2 brings the initiator Met-tRNAi to the preinitiation complex (PIC). Upon start codon selection and GTP hydrolysis promoted by the GTPase-activating protein (GAP) eIF5, eIF2-GDP is displaced from Met-tRNAi by eIF5B-GTP and is released in complex with eIF5. EIF5B promotes ribosomal subunit joining, with the help of eIF1A. Upon subunit joining, eIF5B hydrolyzes GTP and is released together with eIF1A. EIF5 promotes GTP hydrolysis by eIF2, followed by phosphate release. eIF2-GDP has lower affinity for Met-tRNAi than eIF2-GTP, and is released together with its GAP, eIF5. Possible mechanism for coordination between the two steps in translation initiation controlled by GTPases: start codon selection and ribosomal subunit joining, overview | Homo sapiens |
| physiological function | eukaryotic translation initiation is a multistep process requiring a number of eukaryotic translation initiation factors (eIFs). Two GTPases play key roles in the process. EIF2 brings the initiator Met-tRNAi to the preinitiation complex (PIC). Upon start codon selection and GTP hydrolysis promoted by the GTPase-activating protein (GAP) eIF5, eIF2-GDP is displaced from Met-tRNAi by eIF5B-GTP and is released in complex with eIF5. EIF5B promotes ribosomal subunit joining, with the help of eIF1A. Upon subunit joining, eIF5B hydrolyzes GTP and is released together with eIF1A. Possible mechanism for coordination between the two steps in translation initiation controlled by GTPases: start codon selection and ribosomal subunit joining, overview | Homo sapiens |
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