Question

The histone proteins are among the most slowly evolving proteins. For example, a histone protein called histone H4 in cows and peas differs by only 2 amino acids among a total of about 100. A reason why histone proteins evolve so slowly is their function: These proteins bind with the negatively charged phosphate groups in double-stranded DNA, so the proteins must be rich in the basic amino acids lysine and arginine. Therefore, these amino acids cannot be replaced without disrupting the histone's structure and function.
a) True
b) False

Answer 1

The statement is true, histones are proteins that are high in the amino acids lysine and arginine, making them extremely basic in their structure.

Histones control the degree of packaging of DNA during the processes of gene expression, replication or repair of hereditary material, among many others.

Histones H2A, H2B, H3 and H4 are small and basic proteins that are highly conserved in evolution and are composed of a globular domain at the carboxy-end, and by regions known as "tails", which are found at the amino-terminal end.

These tails are high in the amino acids lysine and arginine, which give them a positive charge.

This region is the site of numerous post-translational modifications that, it has been proposed, would modify the histone charge, altering the accessibility of the DNA and the protein / protein interactions with the nucleosome.

Chromatin compaction occurs due to the interaction between the negative charges of DNA and the positive charges of amino acids, mainly located on the tails of histones H3 and H4.

Therefore, we can conclude that the modifications on the amino acids lysine and arginine that form the basic part of the histone structure alter their functions.

Learn more about histone proteins here: brainly.com/question/14984828