How To Get A tRNA Sequence From A DNA Sequence

The process of producing protein from a DNA – deoxyribonucleic acid – sequence includes two major steps: transcription and translation. During transcription, a messenger ribonucleic acid, or mRNA, is created from the DNA template. This mRNA combines with a ribosomal RNA, known as rRNA, and transfer RNA, or tRNA, complex to translate the mRNA code into an amino acid sequence, a protein. DNA is made up of a sequence of nucleotide bases. The four bases are adenine, thymine, guanine and cytosine. The sequence in which these bases occur on a strand of DNA ultimately codes for the production of certain proteins. After the cell manufactures the proteins, they can be used structurally or in various metabolic processes.

Step 1

Create an mRNA transcript of the DNA sequence. Each base in DNA matches another base. Pictures of DNA typically show it in a double helix, with the bases on one strand connecting via bonds to the complementary bases on the opposite strand. Complementary bases are: adenine (A) and thymine (T), and cytosine (C) and guanine (G). So if one strand of DNA reads A-C-G-C-T-A, then the complementary strand is T-G-C-G-A-T. You can find the sequence of the mRNA transcript in the same way, by using the complements of the bases shown in the DNA sequence. RNA, however, does not contain the base thymine (T); instead, this base is replaced with uracil (U). When you come across an adenine (A) in the DNA sequence, match it with a uracil (U).

If the DNA sequence is A-A-T-C-G-C-T-T-A-C-G-A, then the mRNA sequence is U-U-A-G-C-G-A-A-U-G-C-U.

Step 2

Create a tRNA anti-codon sequence from the mRNA transcript. Each tRNA has a set of three bases on it known as an anti-codon. The anti-codon matches complementary bases in the mRNA sequence. To determine the overall anti-codon sequence that will match a strand of mRNA, simply retranscribe the RNA sequence; in other words, write out the complementary bases. Using the previously noted mRNA sequence, the tRNA anti-codon sequence is A-A-T-C-G-C -U-U-A-C-G-A.

Step 3

Break the tRNA sequence you found into three-base sets. Because anti-codons are made up of three bases at a time, a better way to write the anti-codon sequence A-A-T-C-G-C -U-U-A-C-G-A is AAT-CGC-UUA-CGA.