Structural Basis for Ligand Binding to the Guanidine-I Riboswitch
| Autor: | Scott A. Strobel, Yong Xiong, Caroline W Reiss |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Models
Molecular 0301 basic medicine Riboswitch RNA Folding Arginine Stereochemistry Guanine Guanidinium Cation Crystallography X-Ray Ligands Article 03 medical and health sciences chemistry.chemical_compound Structural Biology Guanidine Molecular Biology Clostridiales 030102 biochemistry & molecular biology Chemistry Hydrogen Bonding Aptamers Nucleotide Ligand (biochemistry) RNA Bacterial Crystallography 030104 developmental biology Cobalamin riboswitch Helix Nucleic Acid Conformation |
| Zdroj: | Structure. 25:195-202 |
| ISSN: | 0969-2126 |
| DOI: | 10.1016/j.str.2016.11.020 |
| Popis: | The guanidine-I riboswitch is a conserved RNA element with approximately 2,000 known examples across four phyla of bacteria. It exists upstream of nitrogen metabolism and multidrug resistance transporter genes and alters expression through the specific recognition of a free guanidinium cation. Here we report the structure of a guanidine riboswitch aptamer from Sulfobacillus acidophilus at 2.7 Å resolution. Helices P1, P1a, P1b, and P2 form a coaxial stack that acts as a scaffold for ligand binding. A previously unidentified P3 helix docks into P1a to form the guanidinium binding pocket, which is completely enclosed. Every functional group of the ligand is recognized through hydrogen bonding to guanine bases and phosphate oxygens. Guanidinium binding is further stabilized through cation-π interactions with guanine bases. This allows the riboswitch to recognize guanidinium while excluding other bacterial metabolites with a guanidino group, including the amino acid arginine. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|