6CK4
G96A mutant of the PRPP riboswitch from T. mathranii bound to ppGpp
Summary for 6CK4
| Entry DOI | 10.2210/pdb6ck4/pdb |
| Descriptor | PRPP riboswitch, GUANOSINE-5'-TRIPHOSPHATE, MAGNESIUM ION, ... (7 entities in total) |
| Functional Keywords | riboswitch, ykkc, prpp, ppgpp, rna |
| Biological source | Thermoanaerobacter mathranii |
| Total number of polymer chains | 4 |
| Total formula weight | 155114.49 |
| Authors | Reiss, C.W.,Knappenberger, A.J.,Strobel, S.A. (deposition date: 2018-02-27, release date: 2018-06-20, Last modification date: 2024-03-13) |
| Primary citation | Knappenberger, A.J.,Reiss, C.W.,Strobel, S.A. Structures of two aptamers with differing ligand specificity reveal ruggedness in the functional landscape of RNA. Elife, 7:-, 2018 Cited by PubMed Abstract: Two classes of riboswitches related to the guanidine-I riboswitch bind phosphoribosyl pyrophosphate (PRPP) and guanosine tetraphosphate (ppGpp). Here we report the co-crystal structure of the PRPP aptamer and its ligand. We also report the structure of the G96A point mutant that prefers ppGpp over PRPP with a dramatic 40,000-fold switch in specificity. The ends of the aptamer form a helix that is not present in the guanidine aptamer and is involved in the expression platform. In the mutant, the base of ppGpp replaces G96 in three-dimensional space. This disrupts the S-turn, which is a primary structural feature of the RNA motif. These dramatic differences in ligand specificity are achieved with minimal mutations. aptamers are therefore a prime example of an RNA fold with a rugged fitness landscape. The ease with which the aptamer acquires new specificity represents a striking case of evolvability in RNA. PubMed: 29877798DOI: 10.7554/eLife.36381 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.097 Å) |
Structure validation
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