Homework SourseCertain proteins associate tightly with DNA by forming ionic
Certain proteins associate tightly with DNA by forming ionic bonds with the DNA backbone.
(A) Which amino acids have side chains that could form these ionic bonds with DNA? Explain.
(B) Assuming that the DNA-binding proteins contain an abundance of the amino acid residues mentioned in part a how would the proteins behave during electrophoresis? Explain.
Certain proteins associate tightly with DNA by forming ionic bonds with the DNA backbone.
(A) Which amino acids have side chains that could form these ionic bonds with DNA? Explain.
(B) Assuming that the DNA-binding proteins contain an abundance of the amino acid residues mentioned in part a how would the proteins behave during electrophoresis? Explain.
(A) Which amino acids have side chains that could form these ionic bonds with DNA? Explain.
(B) Assuming that the DNA-binding proteins contain an abundance of the amino acid residues mentioned in part a how would the proteins behave during electrophoresis? Explain.
Solution
Answer:
The majority of the DNA in the eukaryotic cells is packaged into nucleosomes, where certain proteins associate tightly with DNA by forming ionic bonds with the DNA backbone. These proteins are called as histone proteins.
(A) The amino acids having positively-charged side chains could form ionic bonds with the negatively-charged DNA molecule. Example: Lysine, Arginine
(B) When DNA-binding proteins contain an abundance of the amino acid residues having positively-charged side chains, the proteins will behave as cations and migrate towards the negative electrode in the electrophoresis.
