Histones - ia ... Ka kūlana o histones i loko o ka DNA

Nukeleaʻakika DNA me loko o ka nucleus o eukaryotic keena, olelo hoopomaikai pūʻolo helu hoomaikai i kūikawā hale. Ma cytology ka mea, komo i ka kūikawā inoa - histones. He Heʻakika'amino i SafeSearch ke kumu o Nine Inch waiwai. Lākou 'ole a me ka oihana mau hana i loko o ka halepaahao, e e kūkākūkā i loko o kēia' atikala.

DNA ua hoʻonohonoho 'ia i loko o ka nucleus

I mea e "laila kaomi" lōʻihi polynucleotide lei o ka DNA i microspace aeea nucleus ma laila nō auaneʻiʻoukou "'ōwili hao" - nā polokina, histones. Ka mea, i papalua-ili kālepa ma ua wahi iho la deoxyribonucleicʻakika. Kēia 'ole, Aia ma ka karyoplasm ua kapaia he nucleosome. Biochemical haʻawina hōʻike i histone kumuʻiʻo i hoʻonohonoho 'ia i loko o kekahi mau hoʻololi' ia: histone H1 / H5, H2A, H2B, H3, H4. Ka muaʻakika'amino o keia papa ua kapaia he linker, ka mea'ē aʻe bipi. Mau histone nā polokina kuahene nucleosome.

Hiʻona o ka 'ole o ka nucleosome peptides

Nine Ka Ikepili hoʻokumu i ka oiaio o excessive ka maʻiʻo ma ke kāna mau 'ōlelo histone nā lātoma o'amino nāʻakika e like me lysine a me ka arginine. Ka mua he mea nui, a me ka 'ē aʻe hapa' ia 'interchangeable a me ka mea i loaʻa i loko oʻaneʻane a pau peptides. Histone nā polokina loaa oi maikaʻi e mālama ai ma o ka'aminoʻakika residues. Ka mea, neutralize i ka hopena maikaʻi 'āhewa' ana o ka huina PO ₄ ^3- anions, pū i loko o ka DNA. Kekahi hiʻona o ka 'ole o kēia mau nā polokina moe ana ma ka oiaio i ka mea i aneane'ālike ma meaola pili ana i ke aupuni o ka mea kanu, holoholona a me nā fungi.

Mai histones - nā polokina o ka Kora naʻEsau, ka mea, e ku pono ana i kona 'ole, hiki ke komo i loko o ka keʻano o ka hanaʻana' ia i loko o karyoplasm. No ka laʻana, ka mea nui a hiki i ka Ekolu a kaʻina hana H1ʻakika'amino - histone kumuʻiʻo hoʻokoe iho i nucleosomes i kekahi hapa o ka chromatin i loko o ka pololei oe, olelo hoopomaikai Kora naʻEsau. Nō hoʻi, ma ka hihia o ka poho DNA loci, no laila,-kapaʻia kāna mau 'ōleloʻakika'amino Lolina nā lātoma i komo i loko o ka? Aiiio o kēia mau wahi.

kāna mau 'ōleloʻakika'amino

Ka mea, IeXAaAeAaIEN ka 'ole o ka nucleosome, a he ehaʻano o nā lātoma kapa H2A, H2B a me H3 a me H4. Nā nucleosomes iʻelua o kēlā me kēia 'ano o ka lātoma, ua kapaia octamer ia i ka' ole. Ke lātoma o deoxyribonucleic kāna mau 'ōlelo nā polokina a me ke ano ma waena o ia hydrophobic, hydrogen a me ka covalent paa. Nā polokina, histones nō ma ka 'ōlelo o ka nucleosome. ka mea, i pihaʻi me unstructured NC-huelo. Kēia mau māhele komo o 15-30'aminoʻakika residues a e hoʻomau ana ma ka epigenetic keʻano o ka hanaʻana i ka pāʻana'ōewe hōʻike. Kora histones kikowaena hapa nucleosomes i uuku hakakino kaumaha, i loko o kā lākou mau mea, e like me ka huelo haʻawina islets i kakauiaʻi maluna hydrophobic monomers kumuʻiʻo valine, proline, Lezina methionine.

Recent noiʻi i loko o ke kula o ka biochemistry i alakai aku ai i ke kuhiakau o ka histone kuhi. Akä naÿe i ka aaiaoe kivila mea paʻa no nāʻano o ke kelepona hele ola ma ka Honua, me ka histone kuhi mea ee iaaanu aey. Kēia manawa 'o ia hoʻi modifying ka huelo haʻawina o na peptides mai ana ka acetylation naoh, methylation, phosphorylation. A pau kēia mau Nine Inch keʻano o ka hanaʻana ana i loko o ke alo o multienzyme eiiieaenu. Ma muli o ka mea biochemical keʻano o ka hanaʻana, ka modifying Kora naʻEsau histones, a me ka hoʻoponopono i wahi olelo o nā'ōewe i ka pāʻana intranuclear reactions pili i DNA:? Aiiio, Ekolu a, replication. Iho ma lalo o ka aoao o ka chromatin histone kuhi loli undergoes remodeling, oa hoʻololi kona'ōpala i loko o ka nucleosome (wepa ehiku ia paha, ma ka mea ku ole, loosens).

linker kumuʻiʻo

Histone H1 ua ma ka chromatin, ua pili i ka hapa ma waho o ka nucleosome, a i hoopaa mai ai maluna iho supercoil deoxyribonucleicʻakika. Kona fixation ia lŘlŘ i wahi tetramer iloko olaila a mauʻakika'amino nā lātoma H3 a me H4 mau nā lātoma. Na elele o ka papa, a me ka papa o nā manu kolo ma kaʻulaʻula koko keena kahi o ka histone H1 linker kumuʻiʻo loaʻa kekahi H5.

H1ʻakika'amino maupaʻa HMJB-kikowaena - he mall hapa, me ka hola 80'aminoʻakika residues. He mea kokoke i ka ia i loko o ka hapanui meaola, me mea kanu, holoholona a me nā kānaka. Kēia kāʻei mea ole malalo o ke hoʻololi 'a me ka mea makeʻe kulana. ʻakika'amino N1 i mau ano o māhele kŰia ke kau: ka hauneneʻe puni globule a me ka wehewehe nui loa aku - i loko o tertiary palapala. I ka la mahope ia lŘlŘ ka wā e olelo aku ke aloha C-maʻi māhele o ka histone a hiki i ka DNA-paa kāʻei kapu. Ke linkerʻakika'amino ua 'Imi' ole i loko o ka hoʻopiliʻana o ka 'ike mai ka'ōewe e mRNA lātoma, he pakiko-a pāpālua hoʻi DNA keʻano o ka hanaʻana, e like me ka pono me ia ma ka? Aiiio o poino kona loci. 'O kēia ka liluwelo kūlana o histones i loko o ka DNA.

E like me nā polokina kuahene octamer

Haʻaleleʻakika'amino H1, nāʻano o nā histones kapa bipi, wehewehe aku e lawa ductility, e hana i ka Lolina palapala. No ka laʻana, H2A i ka mea kiʻekiʻe loa helu ana o ka hoʻololi 'ana: H2AZH2AX MACROH2A. Ka mea, oko mai kēlā 'ē aʻe:

• C-maʻi'aminoʻakika kaʻina.
• Location i loko o ka genome.

No ka laʻana, histone Lolina H2ABbd interconnected me chromatin ma i DNA EKOLU ia lŘlŘ. MACROH2Aʻakika'amino mea i loko o interphase chromosomes. Cytological haʻawina ka mea i loaʻa i ka histone H4 Lolina 'ano apau loa i ua hōʻike, akā, ka mea hiki ke hana i kekahi nui helu o ka covalent makaukau na kaula paa a me nā nā polokina pili ana i ka octamer nucleosomes. Penei,ʻepekema manaoio i na histones - he kūikawā pūʻulu o nā polokina i mea kokoke hapa o ka chromatin o nā mea a pau ke kelepona hele ano o ke ola.

Pehea e hoahu 'ike e pili ana i na histones i loko o ka genome

Ua hiki e ua kūkākūkāʻia i nā bipi, a me ka linker histone Lolina encoded i loko o ka'ōewe he mau huhui hoikeia ma ka kemikala pae o ka halepaahao i ka ola kalapona. No ka laʻana, no ka kanaka hereditary kāna moʻolelo ka pae kapa HIST1 ka mea, he 35 nā'ōewe aia i loko o ka hora aono a hiki somatic chromosome paʻa. HIST2 huiwaina maupaʻa eono nā'ōewe hoʻopā'ālua histones, a me ka chromosomal wahi o ka hui mua. Ua hoi kekahi mau he locus HIST3, ec na nā'ōewe ekolu. I ka umikumamalua o ka paʻa o kekahi'ōewe hoʻopā'ālua kekahi histone H4. Interestingly, o ka Kora naʻEsau kumuʻiʻo nā'ōewe i introns, a me nā'ōewe o ka Lolina histones, ma ka mea ku ole, komo ia, a ua hoʻopuehuʻia ma ka genome.

E hōʻuluʻulu manaʻo, ua ike makou i na histones - nā polokina ua komo i loko o ke kau o ka makalii o ka DNA i loko o ka nucleus, akā, i loko o ka keʻano o ka hanaʻana o ka rula, hoʻoponopono a me Ekolu a lawe wahi i loko o laila.