Navigation Links
Nucleosome


A nucleosome is the fundamental repeating subunit of eukayotic DNA, and is made up of DNA and histone proteins. It is found in the cell nucleus in eukaryotes. All chromatin (except for that packaged in the sperm nucleus) consists of nucleosomes. Nucleosomes can be seen with an electron microscope as bead-like structures along the DNA.

Structure

The histones make up the central core particle of the nucleosome. The DNA is wrapped around this protein complex in two turns, with each turn consisting of about 80 base pairs. Together with the DNA linking two nucleosomes, there are about 200 bps of DNA per nucleosome.

Nucleosomes are involved in processes ranging from compaction of DNA to transcriptional control, and appear to be major carriers of epigenetically inherited information as well. Repeating nucleosomes with intervening "linker" DNA form the 10-nm-fiber, known descriptively as "beads on a string", and have a packing ratio of ~6, compared to "free" DNA (per nm length). A chain of nucleosomes can be arranged in a 30-nm-fiber, a compacted structure (once thought to be a helical solenoid, but now considered likely to exist as a zig-zag structure in vivo) with a packing ratio of ~40. The H1 histone stabilizes this structure. Beyond 30 nm fiber the structure of chromatin is poorly understood, but it is classically suggested that the 30 nm fiber is arranged into loops along a central protein scaffold to form transcriptionally active euchromatin. Further compaction leads to transcriptionally inactive heterochromatin.


'"/>


(Date:6/2/2016)... June 2, 2016 Perimeter Surveillance ... Unmanned Systems, Physical Infrastructure, Support & Other Service  ... visiongain offers comprehensive analysis of the global ... will generate revenues of $17.98 billion in 2016. ... Inc, a leader in software and hardware technologies for ...
(Date:5/12/2016)... WearablesResearch.com , a brand of Troubadour ... from the Q1 wave of its quarterly wearables survey. ... receptivity to a program where they would receive discounts ... company. "We were surprised to see that ... LaColla , CEO of Troubadour Research, "primarily because there ...
(Date:4/26/2016)... India and LONDON ... Infosys Finacle, part of EdgeVerve Systems, a product ... and Onegini today announced a partnership to integrate ... solutions.      (Logo: http://photos.prnewswire.com/prnh/20151104/283829LOGO ... to provide their customers enhanced security to access ...
Breaking Biology News(10 mins):
Other biology definition