Which of the following is not true of the N terminal tail of these histones? The core histones are small, basic proteins that ha
ve a globular domain at the C-terminus and a long extended conformation at the N-terminus. A. It is subject to a covalent modifications
B. It extends out of the nucleosome core
C. It binds to DNA in a sequence-specific manner
D. It helps DNA pack tightly
E. It contains lysine residues
The correct answer is option C. "It binds to DNA in a sequence-specific manner".
Explanation:
It is not true that histones bind to DNA in a sequence-specific manner. Histones and DNA have nonspecific bindings (occuring at any DNA sequence) given mostly by electrostatic interactions. DNA is a macromolecule that is highly negatively charged because of its phosphate residues, while histones are proteins that are highly positively charged because of its high content of positively charged amino acids. In consequence, the binding of histones and DNA occurs mostly in a nonspecific fashion given by electrostatic interactions.
