Question

Which of the following post-translational modifications will alter amino acid charge?

a) Acetylation of lysines
b) Phosphorylation of serines
c) Methylation of lysines
d) Palmitoylation of cysteines
e) Choices (a) and (c) are both correct.

Answer 1

The correct post-translational modification that alters amino acid charge is b) phosphorylation of serines, as it adds a negatively charged phosphate group to the amino acid residue.

Step-by-step explanation:

The question relates to post-translational modifications of proteins that can alter the amino acid charge. Specifically, the question asks which of the following modifications affects amino acid charge: acetylation of lysines, phosphorylation of serines, methylation of lysines, palmitoylation of cysteines, or options (a) and (c).

To answer this question, one must understand the chemical nature of these modifications. Acetylation involves the addition of an acetyl group, which does not result in a charge change. Methylation adds a methyl group, which is also neutral. In contrast, phosphorylation adds a negatively charged phosphate group, which will alter the charge of the amino acid residue. Palmitoylation attaches a palmitoyl group, which does not influence the charge either.

Therefore, the correct answer is b) Phosphorylation of serines, which adds a negative charge due to the phosphate group.