Histones - reira ... te tūranga o histones i te DNA

ngā karihi waikawa DNA i roto i te karihi o ngā pūtau eukaryotic, kiato whakawhetai tākai ki ngā hanganga motuhake. I roto i te cytology kakahuria e ratou he ingoa motuhake - histones. Ko te peptide e whakaatu nga āhuatanga taketake matū. Ratou hanganga me ngā mahi whakamana i roto i te pūtau, ka e kōrero i roto i tenei tuhinga.

whakaritea te DNA i roto i te karihi

I roto i te tikanga ki te "kotēhia" mekameka polynucleotide roa o te DNA i roto i te microspace karihi pūtau reira e rawe ki "pōkai" - pūmua, histones. E tukitukia e ratou te miro rua-paea waikawa deoxyribonucleic. ka karanga tenei hanganga, kei roto i te karyoplasm te te nucleosome. whakakitea rangahau matüora e histone pūmua whakaritea i roto i te maha o ngā whakarerekētanga: H1 histone / H5, H2A, H2B, H3, H4. huaina te peptide tuatahi o tenei rārangi ko te linker, te tahi atu kau. Ēnei pūmua histone hanga nucleosome.

Āhuatanga o te hanganga o peptides nucleosome

whakapumautia tātari matū te meka o te ihirangi nui i roto i te rāpoi ngota histone matua o waikawa amino pērā i lysine me arginine. Ko te tuatahi Ko faufaa me te tahi atu wāhanga whakawhiti, me te he reira i roto i te tata peptides katoa. pūmua Histone kohikohi tiaki pai i te taikaha i runga i nga toenga waikawa amino. e haamou i ratou i te utu kino o te katoa PO ₄ ^3- tīhiko, ngā i roto i te DNA. Ko tētahi atu āhuatanga o te hanganga o enei pūmua takoto i roto i te meka e ko te reira i tata ōrite i roto i te kaiao no ki te rangatiratanga o te tipu, kararehe me harore.

Mai histones - pūmua ko te matua, e tika ana ki tona hanganga ratou, taea whai wāhi i roto i te tukanga tupu i roto i te karyoplasm. Hei tauira, ko te nui tino ki te patohanga tukanga H1 peptide - pūmua histone pupuri nucleosomes he wahi o te pūpūira i roto i te maau, matua kiato. E whai wāhi ana hoki, i roto i te take o te kino DNA te huanui, pera-ka karanga rāpoi peptide kē matua i roto i te hanga o enei wahi.

peptide matua

tautuhi ratou te hanganga o te nucleosome, e ngā o ngā momo e whā o ngā rāpoi ngota i huaina H2A, H2B ko H3 ko H4. Ko te nucleosomes e rua o ia momo o rāpoi ngota, ka karanga te hanganga taua te octamer. Ko te rāpoi ngota o te pūmua matua deoxyribonucleic me puka i waenganui ratou hydrophobic, hauwai me here kotuari. Pūmua, he histones i te matua o te nucleosome. Kei roto hoki ratou hanganga NC-hiku. Enei wahi ngā o 15-30 toenga waikawa amino me he wāhi i roto i te tukanga epigenetic e whakahaere te whakaaturanga ira. histones matua nucleosomes wahi pokapū i taimaha rāpoi iti, i roto i o ratou wāhi, pērā i roto i te moutere hiku wahi waetahi hydrophobic pūmua valine, proline, Lezina methionine.

rangahau Tata i te mara o te mataora i arahina ki te whakapae o te waehere histone. I roto i te rerekē ki te waehere iranga he ao mō ngā momo katoa o te ora pūtau i runga i te whenua, he tāupe te waehere histone. tikanga o tēnei wā whakarerekē i te wahi hiku o nga peptides hua i te acetylation tauhohe, methylation, phosphorylation. enei tukanga matū katoa puta i roto i te aroaro o multienzyme complexes. Nā ki taua tukanga matüora, te histones matua whakakē, me e whakatikatikanga wahi faaiteraa o ira e whakahaere tauhohe intranuclear e pā ana DNA: te hanga, te tuhi, tukuruatanga. Ia i raro i te mana o te huringa waehere histone pūpūira te whakamamaetia TEETH, arā te huri tona tākai i roto i te nucleosome (hiri ai reira ranei, i runga i te anga ke, wetekina).

linker pūmua

Kei roto i te pūpūira, te hono Histone H1 ki te wahi i waho o te nucleosome me tonu ki runga supercoil deoxyribonucleic. puta tōna warea i wāhi tetramer arā, o ngā rāpoi ngota peptide rua H3 me H4 rāpoi ngota e rua. Ko te māngai o te piha haapiiraa, me te piha haapiiraa o manu ngarara i roto i ngā pūtau toto whero hei utu o histone H1 linker pūmua kitea tetahi atu H5.

peptide H1 Kei HMJB-rohe - he wahi hanganga, me ngā toenga waikawa āhua 80 amino. Ko whakaritea e ia te taua i roto i te nuinga o kaiao, tae atu ki ngā tipu, kararehe, me te tangata. e kore he kaupapa ki te whakarerekē tenei rohe, me te he momo. E rua ngā puka o whirihoranga mokowā Peptide N1: he globule tiango me fafauhia - i roto i te puka wānanga. Puta ana te whakamutunga, ina hemo kōrero C-kāpeka rohe o te histone ki nga rohe DNA-here. Kei te whai wāhi te peptide linker i tārua o ngā mōhiohio i te ira ki mRNA rāpoi ngota, he tukanga DNA whaiaro-rearua, me rite i roto i te hanga o pakaru tona huanui. Ko te tūranga koiora o histones i roto i te DNA tenei.

Ka rite ki te hanga i octamer pūmua

Rerekē peptide H1, ki ētahi atu momo o histones i huaina kau, āhuatanga e rawaka te ukanga hanga he puka kē. Hei tauira, H2A kua te maha rawa o akatuke'anga: H2AZH2AX MACROH2A. rerekē ratou i ia atu:

• C-kāpeka waikawa amino raupapa.
• Wāhi i roto i te genome.

Hei tauira, tuati-histone rerekē H2ABbd ki pūpūira i roto i nei puta DNA tuhi. Ko MACROH2A peptide i pūira interphase. rangahau Cytological i kitea ai e kua tāutuhia te puka kē histone H4, engari ka taea e hanga te reira i te tau nui o here kotuari ki ētahi atu pūmua no ki te nucleosomes octamer. Ko te kupu, kaipūtaiao whakapono e nga histones - he rōpū motuhake o te pūmua e he ngā wāhanga o te pūpūira o ngā momo pūtau katoa o te ora.

Me pēhea te ki te rokiroki i ngā mōhiohio e pā ana ki te histones i roto i te genome

Ka taea te tohe te reira e te kau, me te kē linker histone whakawaeheretia i roto i te tautau ira whakahuatia i roto i te wāhanga waihanga o te huringa ora o te pūtau. Hei tauira, mō te rōpū tangata āhuatanga tuku huaina HIST1 ngā reira o 35 ira kei roto i te ono o te rua pūira somatic. HIST2 tautau Kei ono ira whakawaehere histones, me te wāhi pūira o te rua tuatahi. Kei reira hoki te HIST3 wāhi, kei roto i te ira e toru. I roto i te tekau ma rua te rua, ko te kotahi ira whakawaehere he H4 histone. Te mea faahiahia, te ira matua pūmua i introns, me ira o histones kē, i runga i te anga ke, i roto i a ratou, a kua marara, puta noa i te genome.

Hei whakarāpopoto, kua kite matou e nga histones - whai wāhi pūmua kei roto i te whakapanga i te whenu o DNA i roto i te karihi, engari ano hoki i roto i te tukanga o te ture, hanga me te tuhinga tango i te wahi i roto i reira.