DNA to Protein Translation
Translate a DNA or RNA sequence into protein in one frame or all six, with the standard code or a mitochondrial or bacterial one, in one- or three-letter symbols, with the protein's length, mass, isoelectric point and extinction coefficient.
Sequence tool
Translate a sequence
Bare letters, a FASTA record or a GenBank record. Numbers and spaces from a listing are ignored.
Paste a DNA or RNA sequence to translate it.
Worked example
The human insulin coding sequence (NM_000207.3, 333 nt)
- 01ATG GCC CTG TGG … → Met-Ala-Leu-Trp …
- 02111 codons; the last, TAG, is a stop
- 03110 amino acids: preproinsulin, 11,980.8 Da, pI 5.22
Preproinsulin, 110 amino acids beginning MALWMRLLPLL, about 12.0 kDa before its signal peptide and C-peptide are cut away to leave insulin.
How it works
The reasoning behind it
A ribosome reads mRNA three bases at a time, and each triplet, a codon, calls for one amino acid or a stop. Where the reading starts decides which triplets are read: shift by one base and every codon changes. A strand therefore has three reading frames, and its reverse complement three more, six in all.
The genetic code is nearly universal, but not quite. Mitochondria and some bacteria read a few codons differently, so the tool offers NCBI's tables 1 to 5 and 11. With an ambiguity code in a codon, the tool translates it when every possibility agrees (GCN is always alanine) and writes X when it doesn't.
For the protein, the tool adds up the average masses of its amino acids, less a water for each peptide bond; finds the pH at which its charge is zero from the pK values of its ionisable groups; and estimates how strongly it absorbs at 280 nm from its tryptophans, tyrosines and cystines, the way a spectrophotometer measures it.
Questions
Frequently asked
What are the six reading frames?
Three on the strand you pasted, starting at its first, second and third base, and three on the reverse complement. A gene uses one of them. The others usually hit a stop codon every twenty codons or so.
Why does my translation have stops in the middle?
Either the frame is wrong, so try the other two, or the sequence is not all coding: an mRNA has untranslated ends, and a gene from a genome has introns. The ORF finder shows which frame holds the long open stretch.
Which genetic code should I use?
The standard code for nuclear genes of almost any organism, and for most bacteria and viruses. Use the vertebrate mitochondrial table for a mitochondrial gene of a human or other vertebrate, and the bacterial table when you want GTG and TTG treated as start codons in the ORF finder.
How is the molecular weight calculated?
The average masses of the amino acids are added up and a water (18.015 Da) is taken off for each peptide bond. It is the mass of the bare chain: no signal peptide removed, no sugars, phosphates or disulfides counted.
What is the isoelectric point?
The pH at which the protein carries no net charge, where it won't move in an electric field. Below it the protein is positive, above it negative. It matters for ion-exchange chromatography and isoelectric focusing, and for solubility, which is lowest near the pI.
More Calculators
Each one shows its formula and a worked example, so you can check the answer and learn the method.
ORF Finder
Every open reading frame in all six frames, with its position, length and protein, from ATG or any start codon.
Open the toolReverse Complement
The reverse complement, complement or reverse of a DNA or RNA sequence, or DNA written as RNA, from bare letters or FASTA.
Open the toolGC Content Calculator
GC content, base counts, length and molecular weight of a DNA or RNA sequence, with GC along the sequence in a sliding window.
Open the toolPractice the theory with free quizzes in Molecular Biology, Biochemistry, Genetics, Bioinformatics and Biotechnology.