what is the functoin of histones in DNA packaging?
Answers
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heres your answer!!
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→→Histones are positively charged proteins that facilitate the packing of DNA into condensed chromatin fibers. They are basically the TupperwareTM of DNA packaging, and they come in many kitchen-friendly colors. Histones have many arginine and lysine amino acids that easily bind to the negatively charged DNA, based on Paula Abdul's principle that opposites attract. Just kidding on that last part. DNA is highly negatively charged because of the phosphate group of each nucleotide is negatively charged.
⇒Histones are divided into two groups:
→Core histones
→Linker histones
→→Core histones are H2A, H2B, H3, and H4, where two H3/H4 dimers (H3 and H4 hooked together) and two H2A/H2B dimers (these two hooked together) form the octamer (all eight of these guys together). Linker histone H1 basically locks the DNA in place onto the nucleosome and can be removed for transcription while linker histone H5 is a variant of H1 predominantly used in birds.
→One important aspect of histones is that they can be changed to alter how much packing the DNA is capable of. There are several modifications that affect how well DNA is packaged.
→Normally, histones are positively charged molecules, and the addition of methyl groups (methylation) makes them more hydrophobic (water-hating). Hydrophobic molecules tend to stick together, and increasing histone methylation will cause the histones to pack even more tightly than usual.
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