Nucleosome structure
From Proteopedia
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<Structure load='1aoi' size='800' frame='true' align='right' caption='Nucleosoma' scene='60/602771/Proteinas/5' /> | <Structure load='1aoi' size='800' frame='true' align='right' caption='Nucleosoma' scene='60/602771/Proteinas/5' /> | ||
| - | <big><big>'''Nucleosome''' is the basic structure of '''chromatin fiber'''. A nucleosome consists of a core | + | <big><big>'''Nucleosome''' is the basic structure of '''chromatin fiber'''. A nucleosome consists of a core with a '''histonic proteins octamer''' and a '''DNA''' molecule 146 bp long surrounding this core in two complete turns. |
Histonic protein octamer includes four types of proteins: <scene name='60/602771/Histonah2a/1'>H2A</scene>, <scene name='60/602771/Histonah2b/1'>H2B</scene>, <scene name='60/602771/Histonah3/1'>H3</scene> y <scene name='60/602771/Histonah4/1'>H4</scene>. Histonic proteins are organized in dimers so: | Histonic protein octamer includes four types of proteins: <scene name='60/602771/Histonah2a/1'>H2A</scene>, <scene name='60/602771/Histonah2b/1'>H2B</scene>, <scene name='60/602771/Histonah3/1'>H3</scene> y <scene name='60/602771/Histonah4/1'>H4</scene>. Histonic proteins are organized in dimers so: | ||
Revision as of 12:14, 9 February 2016
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Nucleosome is the basic structure of chromatin fiber. A nucleosome consists of a core with a histonic proteins octamer and a DNA molecule 146 bp long surrounding this core in two complete turns. Histonic protein octamer includes four types of proteins: , , y . Histonic proteins are organized in dimers so:
- Two H3-H4 dimers
- Two H2A-H2B dimers
- molecule alrededor del octámero de histonas. Algunos completan el conjunto de la estructura
En las predomina con claridad la estructura secundaria en .
Si localizamos los distintos tipos de residuos de aminoácidos a lo largo del de las proteínas histónicas podemos comprobar que los y los se disponen de manera que estos últimos, en la periferia del , pueden establecer interacciónes electrostáticas con las cargas negativas de . Tal distribución de cargas positivas y negativas, y las interacciones iónicas que entre ellas tienen lugar, confiere una gran estabilidad al conjunto de la estructura.
References
This page is based on 1aoi file from Proteopedia.
1aoi is a 10 chain structure with sequence from Xenopus laevis. The July 2000 RCSB PDB Molecule of the Month feature on Nucleosome by David S. Goodsell is 10.2210/rcsb_pdb/mom_2000_7. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
