Histones - nayo ... Basa histones vari DNA

Nucleic asidhi DNA zvaisanganisira ari musimboti masero eukaryotic, chiine mumapepa nemhaka chinokosha hurongwa. In cytology twavanopfeka zita chairo - histones. Chinhu peptide kuti anoratidza inokosha zvemakemikari ehupfumi. Chimiro chavo uye mashandiro anoitwa muchitokisi, ichakurukurwa munyaya ino.

DNA rakarongwa ari musimboti

Kuti 'nepavaigona "polynucleotide cheni hurefu DNA iri microspace muchitokisi neerekitironi zvirimo chairwo" coils "- mapurotini, histones. Vari kaviri nezano rushava iri muchikuvadza deoxyribonucleic acid. mamiriro ichi, riri karyoplasm anonzi nucleosome. zvidzidzo nokukanganisika kwakaratidza kuti histone mapuroteni yakarongwa okunatsiridza akawanda: histone H1 / H5, H2A, H2B, H3, H4. The peptide muurongwa wokutanga anonzi linker, vamwe mhou. Izvi histone mapurotini kuumba nucleosome.

Zvakakurukurwa sechivako nucleosome peptides

Kuongorora makemikari akasimbisa chokwadi wokunzwa tigutsikane ari makirisito histone mamorekuru ose amino acids akadai lysine uye arginine. Chokutanga kunokosha uye nezvimwe ubatanidzwewo kuchinjaniswa uye aripo anenge peptides zvose. Histone mapuroteni kuunganidza zvakawandisa mutariri akanaka pamusoro amino asidhi residues. Ivo neutralize akaipa mhosva zvachose PO ₄ ^3- anions, vanobatanidzwa DNA. Chimwe chinoratidza sechivako mapuroteni izvi iri chokwadi kuti anenge zvakakura zvinenge kuva umambo zvinomera, mhuka uye hunokuvadza.

Sezvo histones - mapuroteni ndiyo chinoumba, zvinokonzerwa ayo mamiriro anogona kubatanidzwa kwemasayendisiti zvichiitika karyoplasm. Somuenzaniso, chinonyanya kukosha kune transcription muitiro H1 peptide - histone mapuroteni ukaramba nucleosomes inhengo chromatin zvakarongeka, chiine core. Uyewo, kana kukuvara DNA loci, dzinonzi makirisito peptide musiyano wezvinyorwa mamorekuru munyaya yokugadzirisa zvikamu izvi.

Musimboti peptide

Ivo rinotsanangura nemamiriro nucleosome randinogara pakubhadhara mana mamorekuru anonzi H2A, H2B uye H3 uye H4. The nucleosomes vari vaviri neimwe mhando Morekuru, chivakwa akadaro anonzi octamer. The morekuru deoxyribonucleic chinoumba mapuroteni uye chimiro pakati pavo hydrophobic, hydrogen covalent zvisungo. Mapuroteni, histones vari chinoumba yacho nucleosome. ivo dzinewo unstructured NC-miswe. zvikamu izvi ine 15-30 amino asidhi residues uye vanobatanidzwa mune epigenetic pezvakaitwa kuti kudzora Gene okuti. Core histones chakagadzirwa mugove nucleosomes vane diki samolecular uremu, munzvimbo dzavo, kusiyana muswe migove nezviduku ine hydrophobic monomers mapuroteni valine, proline, Lezina methionine.

Kutsvakurudza kuchangobva kuitwa mumunda nemakemikari omuviri zvakatungamirira kuti pfungwa yacho histone remitemo. Kusiyana majini code nokudenga kuti marudzi ose cellular upenyu panyika, histone code shanduka. Izvi rinoreva kunatsiridza muswe zvikamu peptides kunokonzerwa kubva acetylation zvakaitwa, methylation, phosphorylation. makemikari pezvakaitwa zvose izvi zvichiitika pamberi multienzyme zvivako. Nokuda nokukanganisika urongwa zvakadaro, kunatsiridza chinoumba histones, uye kuchinja kunoitika okuti majini kuti kudzora intranuclear siyana chokuita DNA repair, transcription, kuberekana. Pachake pasi pokudzora kwomudzimu chromatin histone remitemo kuchinja kaviri yagadziriswa, kureva kuchinja kavha yacho iri nucleosome (anodzivira kana nekusiyana, Nokusunungura).

linker mapuroteni

Histone H1 zviri chromatin, zvakabatana rokunze chikamu nucleosome uye anoramba pacho supercoil deoxyribonucleic acid. Kuda kutamba Its ndepana nzvimbo tetramer zvinosanganisira maviri peptide mamorekuru H3 uye H4 mamorekuru maviri. The vamiririri mukirasi uye boka shiri zvinokambaira muropa masero matsvuku pachinzvimbo histone H1 linker mapuroteni akawana mumwe H5.

H1 peptide unotora HMJB-nzvimbo - a STRUCTURAL mugove, vanenge 80 amino asidhi residues. Ndiye anoita zvakafanana mune zvinenge dzakawanda, kusanganisira zvinomera, mhuka uye vanhu. inotongwa ichi hachisi pasi nadzurudzo uye kuchinja. Peptide n1 ane siyana spatial configurations maviri: a rakabhuroka globule uye zvakaitika - mune tertiary chimiro. The yokupedzisira kunoitika yokukurukurirana ndapererwa C-chinouraya munharaunda histone kuti DNA-tichisunga nzvimbo. The linker peptide iri kuitika akatevedzera mashoko kubva Gene kusvikira mRNA Morekuru, kuzvipira doubling DNA pezvakaitwa, uyewo yokugadzirisa zvakakuvadza loci kwayo. Ndiyo zvipenyu rinoitwa histones vari DNA.

Sezvo mapuroteni anoumba octamer

Kusiyana peptide H1, mamwe marudzi histones anonzi yemombe, vaine ductility zvakakwana kuti vaumbe musiyano wezvinyorwa fomu. Somuenzaniso, H2A ane soro nhamba okunatsiridza: H2AZH2AX MACROH2A. Vakasiyana mumwe:

• C-chinouraya amino asidhi kutevedzana.
• Location ari genome.

Somuenzaniso, histone musiyano wezvinyorwa H2ABbd interconnected pamwe chromatin umo DNA transcription kunoitika. MACROH2A peptide iri interphase okutodza. Zvidzidzo Cytological zvakanzi Vakawana kuti histone H4 musiyano wezvinyorwa siyana zvave kuzivikanwa, asi zvinogona kuumba vazhinji covalent zvisungo nemamwe mapuroteni enzvimbo yacho octamer nucleosomes. Saka, masayendisiti anodavira kuti histones - rinokosha boka mapuroteni kuti vari kushanda chikamu chromatin ose cellular zvipenyu.

How kuchengeta ruzivo pamusoro histones vari genome

Inogona angapokana kuti mombe, uye linker histone musiyano wezvinyorwa encoded mu majini masumbu kwakunoitwa chakaita zvokugadzirwa chokutambudzika sero upenyu yatinofema. Somuenzaniso, nokuti munhu nhaka unhu boka rinonzi HIST1 inoitwa majini 35 iri rechitanhatu somatic chromosome peya. HIST2 sumbu unotora majini nhanhatu yeEncoding histones, uye chromosomal nzvimbo munhu wokutanga peya. Rinewo munhu locus HIST3 kuitika kwemajini matatu. Mugore rechigumi nemaviri vaviri ndeimwe Gene yeEncoding munhu histone H4. Sezvineiwo, chinoumba mapuroteni majini vane introns, uye majini ose musiyano wezvinyorwa histones nekusiyana, ane navo uye vakapararira munyika genome.

Kuti muchidimbu, taona kuti histones - mapuroteni rinobatanidzwa kuisa tambo kuti DNA iri musimboti, asiwo dzinotsanagura murau, kugadziriswa uye transcription kutora nzvimbo mauri.