Transfer RNAs (tRNAs) are responsible for the conversion of nucleotide sequence of mRNA into the protein sequence. There are specific tRNAs for each major amino acid, and the elongation of polypeptide chain can take place only after the successful interaction between the codon of mRNA and anticodon of tRNA.
Lehninger, A., Nelson, D. and Cox, M. (2005). Lehninger principles of biochemistry. New York: W.H. Freeman and Co.