| Autor: |
Varshney, D., Petit, A.P., Bueren-Calabuig, J.A., Jansen, C., Fletcher, D.A., Peggie, M., Weidlich, S., Scullion, P., Pisliakov, A.V., Cowling, V.H. |
| Jazyk: |
angličtina |
| Rok vydání: |
2016 |
| Zdroj: |
'Nucleic Acids Research ', vol: 44, pages: 10423-10436 (2016) |
| ISSN: |
0305-1048 |
| Popis: |
Maturation and translation of mRNA in eukaryotes requires the addition of the 7-methylguanosine cap. In vertebrates, the cap methyltransferase, RNA guanine-7 methyltransferase (RNMT), has an activating subunit, RNMT-Activating Miniprotein (RAM). Here we report the first crystal structure of the human RNMT in complex with the activation domain of RAM. A relatively unstructured and negatively charged RAM binds to a positively charged surface groove on RNMT, distal to the active site. This results in stabilisation of a RNMT lobe structure which co-evolved with RAM and is required for RAM binding. Structure-guided mutagenesis and molecular dynamics simulations reveal that RAM stabilises the structure and positioning of the RNMT lobe and the adjacent α-helix hinge, resulting in optimal positioning of helix A which contacts substrates in the active site. Using biophysical and biochemical approaches, we observe that RAM increases the recruitment of the methyl donor, AdoMet (S-adenosyl methionine), to RNMT. Thus we report the mechanism by which RAM allosterically activates RNMT, allowing it to function as a molecular rheostat for mRNA cap methylation. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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