About the DNA to Protein Translator
This DNA to protein translator converts a DNA sequence into messenger RNA and then into a chain of amino acids using the standard genetic code. Paste a sequence (plain text or FASTA), say whether it is the coding (sense) strand or the template (antisense) strand, choose reading frame 1, 2 or 3, and it returns the mRNA, the codons and the protein in one-letter or three-letter amino-acid codes.
It is designed for biology students working through transcription and translation exercises, and for quick checks of short open reading frames in the lab. By default translation starts at the first AUG start codon and stops at the first stop codon (UAA, UAG or UGA), just as a ribosome would; switch those options off to translate the whole frame and see every stop marked with *.
The tool uses NCBI translation table 1, the standard code used by nuclear genes of most organisms. Mitochondrial and some microbial genomes use variant codes, so a few codons may translate differently there. Spaces, numbers and line breaks are ignored, ambiguous bases such as N translate to X, and up to 30,000 bases are read.
How to use the dna to protein translator
- 1Paste your DNA sequence (FASTA headers, spaces and numbers are ignored).
- 2Choose whether it is the coding strand or the template strand.
- 3Pick the reading frame and whether to start at the first AUG.
- 4Choose one-letter or three-letter amino acid codes.
- 5Copy the mRNA, codons and protein sequence.
Formula and method
Transcription copies the template strand into mRNA that has the same sequence as the coding strand, except uracil (U) replaces thymine (T). If you paste the template strand written 3′→5′, the mRNA is its base-pair complement; if the template is written 5′→3′, the mRNA is its reverse complement.
Translation reads the mRNA three bases at a time from the chosen reading frame (or from the first AUG, which encodes methionine). Each codon is looked up in the standard genetic code, a 64-entry table in which 61 codons specify the 20 amino acids and UAA, UAG and UGA signal stop.
- Codon
- Three consecutive mRNA bases that specify one amino acid or a stop
- Frame
- Which base (1st, 2nd or 3rd) the triplet reading starts from
Worked examples
Short open reading frame (coding strand)
The mRNA is the coding strand with U for T. Reading from AUG: AUG (Met), GCC (Ala), AUU (Ile), GUA (Val), AUG (Met), GGC (Gly), CGC (Arg), then UGA stops translation — 7 amino acids, MAIVMGR.
Template strand written 3′→5′, three-letter codes
Complementing TACAAACCGATT base by base gives mRNA AUG UUU GGC UAA. That translates to Met-Phe-Gly followed by the UAA stop codon.
Whole frame, stops shown
With both options off, every codon in frame 1 is translated: GCU (Ala), UAG (stop), GGA (Gly), UAA (stop). Stops appear as *. The sequence has 5 G/C bases out of 12, or 41.7% GC.
Frequently asked questions
How do you convert DNA to mRNA?+
If you have the coding (sense) strand, simply replace every T with U. If you have the template strand, write the complementary base for each position (A→U, T→A, G→C, C→G) and reverse it if the template was written 5′ to 3′.
What is the start codon?+
AUG (ATG in DNA) is the standard start codon. It codes for methionine, so most newly made proteins begin with Met. Some organisms occasionally use GUG or UUG as alternative starts.
What are the three stop codons?+
UAA (ochre), UAG (amber) and UGA (opal) in mRNA, or TAA, TAG and TGA in DNA. They do not code for an amino acid; release factors end translation when they reach the ribosome.
What is a reading frame?+
Because codons are read in groups of three, a sequence can be divided into triplets starting at the first, second or third base. Each choice is a reading frame and gives a completely different protein; the correct one usually starts with AUG and runs a long way before a stop.
Does this work for mitochondrial DNA?+
Not exactly. Vertebrate mitochondria use a variant code in which, for example, UGA codes for tryptophan and AGA/AGG are stops. This tool uses the standard nuclear code (NCBI table 1).