The anticodon sequence of the tRNA must be complementary to the codon sequence of the mRNA. This means that the bases in the anticodon must be able to form hydrogen bonds with the bases in the codon. For example, the anticodon UAC would be able to bind to the codon AUG, because the U in the anticodon would form hydrogen bonds with the A in the codon, and the C in the anticodon would form hydrogen bonds with the G in the codon.

In addition to the anticodon sequence, the overall structure of the tRNA molecule also plays a role in determining whether or not it can bind to an mRNA. The tRNA molecule must be able to fold into a specific shape that allows the anticodon to be exposed and accessible to the mRNA. This shape is determined by the interactions between the different bases in the tRNA molecule, as well as by the interactions between the tRNA molecule and other proteins.

Finally, the binding of a tRNA molecule to an mRNA is also influenced by the presence of other molecules, such as magnesium ions and GTP. These molecules help to stabilize the interaction between the tRNA and the mRNA, and they also help to ensure that the correct tRNA molecule is bound to the mRNA.