nucleosome

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Nucleosome

The fundamental histone-containing structural subunit of eukaryotic chromosomes. In most eukaryotic organisms, nuclear deoxyribonucleic acid (DNA) is complexed with an approximately equal mass of histone protein. The nucleosome is organized so that the DNA is exterior and the histones interior. The DNA makes two turns around a core of eight histone molecules, thus forming a squat cylinder 11 nanometers in diameter and 5.5 nm in height. A short length of linker or spacer DNA connects one nucleosome to the next, forming a nucleosomal chain that has been likened to a beaded string. This basic structure is found in all forms of chromatin. Nucleosomes have been found in all eukaryotic organisms examined, the only exceptions being some sperm nuclei and the dinoflagellate algae.

A chain of adjacent nucleosomes is approximately sixfold shorter than the DNA it contains. Moreover, chains of nucleosomes have the property of self-assembling into thicker fibers in which the DNA packing ratio approaches 35:1. These observations, and the lack of any obvious catalytic activity, have led to the assumption that the primary function of the nucleosome consists of organizing and packing DNA. See Chromosome, Deoxyribonucleic acid (DNA), Gene

nucleosome

[′nü·klē·ə‚sōm]
(cell and molecular biology)
A morphologically repeating unit of deoxyribonucleic acid (DNA) containing 190 base pairs of DNA folded together with eight histone molecules. Also known as v-body.
References in periodicals archive ?
Subsequent x-ray crystallographic analyses have confirmed his electron microscopy findings as advances in methodology and crystallographic resolution have revealed more and more details of the structure of nucleosomel core particles (2).
For example, our previous study using inorganic nanoparticles as coating materials shows that the inorganic nanoparticles does not significantly change the particle size of ground/coated core particles within the concentration investigated [8], Unlike these elastic inorganic nanomaterials, the viscoelastic polymeric coating materials dissipate a significant amount of collision energy.
Because the viscoelastic polymeric materials can absorb energy through deforming during the collision, the particle size of ground products coated with these polymeric materials becomes larger in general compared to pure core particles.
The function of Laval pipe is to provide the core particles with enough momentum from an existing jet, resulting in the core particles colliding with shell material with enough speed so the core particles could be effectively encapsulated by the shell materials.
The uniform flow containing the shell materials is ejected and collides with the core particles in the section.
It not only avoids the blockage of the nozzle by core and shell materials, but also improves the encapsulated quality of core particles.
3] of the channels also needs to be controlled correctly, and the uniform flow containing the shell materials can be ejected to collide with the core particles at supersonic speed.
At the same time, the RP particles are sent into the entrance of the core particles by a pump and swirled after passing the interior gyrator.
Figure 5 shows the moisture absorption ratio of microencapsulated RP particles as a function of extraction column temperature (80, 120, and 150[degrees]C) in the same experiment conditions of extraction pressure of 16 MPa, mass flow of core particles (0.
The effects of extraction column pressure on the moisture absorption ratio are also studied from 8 to 24 MPa under the same experiment of nozzle temperature (120[degrees]C), mass flow of core particles (0.
The effects of mass flow of core particles on moisture absorption ratios are further studied, as shown in Fig.