Algae, Tree, Herbs, Bush, Shrub, Grasses, Vines, Fern, Moss, Spermatophyta, Bryophyta, Fern Ally, Flower, Photosynthesis, Eukaryote, Prokaryote, carbohydrate, vitamins, amino acids, botany, lipids, proteins, cell, cell wall, biotechnology, metabolities, enzymes, agriculture, horticulture, agronomy, bryology, plaleobotany, phytochemistry, enthnobotany, anatomy, ecology, plant breeding, ecology, genetics, chlorophyll, chloroplast, gymnosperms, sporophytes, spores, seed, pollination, pollen, agriculture, horticulture, taxanomy, fungi, molecular biology, biochemistry, bioinfomatics, microbiology, fertilizers, insecticides, pesticides, herbicides, plant growth regulators, medicinal plants, herbal medicines, chemistry, cytogenetics, bryology, ethnobotany, plant pathology, methodolgy, research institutes, scientific journals, companies, farmer, scientists, plant nutrition
Select Language:
 
   
 
 
Can't find? Try Deep Search with ePlantScience.com  
 
Share |
 
   
Main Menu
If navigation gets difficult, please click the main subject or sitemap to get the list of sub-categories
 
 
 
 
 
Related websites
 
 
 
 
 
 
 
 
Section: Genetics » Organization of Genetic Material » Packaging of DNA as Nucleosomes
 
 
If you like this page, please click:  
 
 
  Spatial arrangement of histones
 
     
 
Content
⇒ Organization of Genetic Material 1.  Packaging of DNA as Nucleosomes in Eukaryotes
⇒ Techniques leading to nucleosome discovery
⇒ Subunit of chromatin - the nucleosome
⇒ Spatial arrangement of histones
⇒ Relation between different nucleosomes
⇒ Solenoid model
⇒ Loops, domains and scaffolds in chromatin
⇒ Chromatin replication and nucleosome assembly
⇒ Phasing and modification of nucleosomes in active genes


Spatial Arrangement of Histones
Arrangement of four histones in the nucleosome was also studied through a study of specific sites in DNA and of their interaction with four histones. These sites could be assigned to specific regions of octamer and, therefore arrangement of eight histone molecules could be described. It was shown that (H3)2.(H4)2 tetramer defines the central turn of the DNA superhelix. H2A and H2B are added as two (H2A).(H2B) dimers one on each face of the tetramer (H3)2.(H4)2 and each binding additional DNA and completing the superhelix (Fig. 27.9). (H3)2 (H4)2. tetramer makes a central 'kernel' associated with two independent dimers H2A-H2B. This explains, why H3 and H4 alone can confer nucleosome like properties on DNA but H2A and H2B can not confer this property.
  
A model for nucleosome with (H3)2.(H4)2 forming a kernel.
Fig. 27.9. A model for nucleosome with (H3)2.(H4)2 forming a kernel.

 
     






     
     
 
 
     
 
Copyrights 2009 © ePlantScience.com