Abstract: Ribozymes exhibiting tRNA synthetase activity and substrate specificity, as well as methods for engineering and producing the same, are disclosed. The ribozymes of the present disclosure comprise a T-box RNA module fused with a flexizyme module. The flexizyme module provides high promiscuity with respect to amino acid substrates and the T-box module provides tRNA substrate specificity. Systems are also described for aminoacylation of suppressor tRNAs with unnatural amino acids (uAAs), such systems comprising the ribozyme previously mentioned, suppressor tRNA, and the desired uAAs. Methods for incorporating a uAA into a growing polypeptide chain using the ribozyme hereof are also provided.