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How do histones acquire positive charges?

Last updated date: 20th Jun 2024
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Hint It's the main protein components of chromatin, which acts as spools around which DNA winds, and plays a task in gene regulation. Without this protein, the unwound DNA in chromosomes would be very long (a length to width ratio of more than 10 million to 1 in human DNA).

Complete answer
In a eukaryotic cell, histones are present and they are alkaline proteins. The nuclei are packaged and order the DNA into structural units called nucleosomes. Due to the presence of basic amino acids like arginine and lysine, they are positive in nature, and it gives the positive charge.

Additional information
There are five important families of histones that exist H1/H5, H2A, H2B, H3, and H4. The core histones are H2A, H2B, H3, and H4 and the linker histones are H1/H5. The core histones all exist as dimers, which are similar therein all of them possess the histone fold domain: three alpha-helices linked by two loops. It is this helical structure that permits for interaction between distinct dimers, particularly during a head-tail fashion (also called the handshake motif). The resulting four distinct dimers were then close to make one octameric nucleosome core, approximately 63 Angstroms in diameter (a solenoid (DNA)-like a particle). During mitosis and meiosis, the dense chromosomes are collected through associations among nucleosomes and other administrative proteins.

Note: Histones are partitioned into authoritative replication-subordinate histones that are communicated during the S-period of the cell cycle and replication-autonomous histone variations, communicated during the whole cell cycle. Gene encoding histone variations are typically not grouped, have introns and their mRNAs are directed with polyA tails. The Complex multicellular organisms have a higher number of histones that perform various functions