Practice making a protein from DNA
Here is the double stranded DNA. It will be making a very short protein.
5' ... A C A T G G A T T A C A C C T G G A A G T A G C A T ... 3' sense strand
3' ... T G T A C C T A A T G T G G A C C G T C A T C G T A ... 5' antisense strand
transcription of antisense strand
mRNA: A U G G A U U A C A C C U G G C A G U A G C U T
(then some processing happens)
(RNA goes from nucleus to ribosome)
Protein: translation of mRNA to protein
MET - ASP – TYR – THR - TRP – GLN STOP
(i) read along the sense strand of DNA until you find ATG. This is the start of all genes.
(ii) Circle the "A" in ATG so you know where to start.
(iii) RNA is copied from the antisense strand. So write the mRNA letters that are opposite to the antisense strand. (e.g where you see a T write an A, A à U, C à G, G à C)
(iv) The starting codon is now AUG in the mRNA
(v) On your RNA strand, make a vertical line every 3 bases (letters).
(vi) Look up each 3 letter codon on the table of amino acids and write down the three letter abbreviation for each amino acid. Do this next to the word "Protein"
(Amino acids can be written as words or abbreviations like this: Arginine or Arg or R)
It should look like MET - ARG - ... - ... - GLN STOP
(but it will have other, different amino acids.).
If you’ve done it correctly, there will be 6 amino acids, then a STOP codon.
(vii) If you want to do another one imagine the the DNA is flipped around, so read right to lift from the 5' end of the anti-sense strand and you’ll come up with another protein.
It doesn’t have a stop code in this sequence.
1st
base / 2nd base / 3rd
base
U / C / A / G
U / UUU / (Phe / F) Phenylalanine / UCU / (Ser / S) Serine / UAU / (Tyr / Y) Tyrosine / UGU / (Cys / C) Cysteine / U
UUC / UCC / UAC / UGC / C
UUA / (Leu / L) Leucine / UCA / UAA / Stop / UGA / Stop / A
UUG / UCG / UAG / Stop / UGG / (Trp / W) Tryptophan / G
C / CUU / CCU / (Pro / P) Proline / CAU / (His / H) Histidine / CGU / (Arg / R) Arginine / U
CUC / CCC / CAC / CGC / C
CUA / CCA / CAA / (Gln / Q) Glutamine / CGA / A
CUG / CCG / CAG / CGG / G
A / AUU / (Ile / I) Isoleucine / ACU / (Thr / T) Threonine / AAU / (Asn / N) Asparagine / AGU / (Ser / S) Serine / U
AUC / ACC / AAC / AGC / C
AUA / ACA / AAA / (Lys / K) Lysine / AGA / (Arg / R) Arginine / A
AUG* / (Met / M) Methionine / ACG / AAG / AGG / G
G / GUU / (Val / V) Valine / GCU / (Ala / A) Alanine / GAU / (Asp / D) Aspartic acid / GGU / (Gly / G) Glycine / U
GUC / GCC / GAC / GGC / C
GUA / GCA / GAA / (Glu/E) Glutamic acid / GGA / A
GUG / GCG / GAG / GGG / G
The codon AUG both codes for methionine and serves as an initiation site (or start codon): the first AUG in an mRNA's coding region is where translation into protein begins. (from https://en.wikipedia.org/wiki/Genetic_code#RNA_codon_table)
Here is human hemoglobin subunit beta (using the one-letter abbrev. for amino acids):
MVHLTPEEKSAVTALWGKVNVDEVGGEALGRLLVVYPWTQRFFESFGDLSTPDAVMGNPK
VKAHGKKVLGAFSDGLAHLDNLKGTFATLSELHCDKLHVDPENFRLLGNVLVCVLAHHFG
KEFTPPVQAAYQKVVAGVANALAHKYH