System setup. We took the initial structure of the tetraloop from the protein data bank (PDB ID -1ZIF) and subsequently edited it to get the target 12-mer sequence of 5′-gggcGAAAgccc-3′. We have used ff99bsc0χOL5 forcefield for the RNA and previously reported amber based forcefield for amino acids. The tetraloop structure was inserted into a cubical box of dimension 9 X 9 X 9 nm 3 and solvated using the TIP3P water model and maintained the target concentration of 300 mM for the systems containing amino acids. For neutralizing the charge of the system, we used Na + and Cl -ions. A schematic representation of the system is shown in Fig. Equilibration and Simulation. Initially, each system was energy minimized using the steepest descent method for 10000 steps, followed by heating it to 300 K in 200 ps using Berendsen thermostat and barostat with a coupling constant of 0.6 ps for each. Restraints of 25 kcal/mol/Å 2 were applied on heavy atoms during the heating process. Thereafter, equilibration was carried out for 2 ns at constant temperature (300 K) and pressure (1 bar) without any restraints using the same thermostat and barostat with coupling constants of 0.2 ps each. Finally, 10 ns unrestrained NVT equilibrations were carried out using the Nosé-Hoover thermostat with a coupling constant of 0.2 ps. During the simulation, the LINCS algorithm was used to constrain all the bonds, and Particle Mesh Ewald (PME) method was used for electrostatics. The distance cutoffs for the van der Waals (vdw) and long-range electrostatic interaction were kept at 10 Å. The time step for each simulation was 2 fs. All the molecular dynamics simulations and free energy calculations were carried out using GROMACS 2019.6 patched with plumed 2.6 .