Histones - izo ... Udindo wa histones mu DNA ndi

Mkati asidi DNA m'gulu phata la maselo eukaryotic, yaying'ono mmatumba kuyamika nyumba wapadera. Mu cytology iwo kuvala dzina wapadera - histones. Ndi peputayidi kuti amasonyeza katundu zofunika mankhwala. Kapangidwe awo ndi ntchito anachita mu selo, ayankhidwa m'nkhaniyi.

DNA ndi bungwe mu phata la

Kuti "Finyani" yaitali polynucleotide unyolo DNA mu microspace selo phata momwemo achilendo "koyilo" - mapuloteni, histones. Iwo awiri Shackleton thonje ndi chilonda deoxyribonucleic acid. nyumba imeneyi ili karyoplasm amatchedwa nucleosome. maphunziro amuzolengedwa anasonyeza kuti histone mapuloteni bungwe mu zosintha zingapo: histone H1 / H5, H2A, H2B, H3, H4. The peputayidi loyamba mndandanda amatchedwa linker, ng'ombe zina. mapulotini histone izi kupanga nucleosome.

Features ya kapangidwe ka mapeputisayidi nucleosome

kusanthula mankhwala anakhazikitsa mfundo za okhutira kwambiri mu pachimake histone mamolekyulu la amino zidulo monga lysine ndi arginine. Choyamba ndi chofunikira ndi zina pang'ono mosinthana ndi alipo pafupifupi mapeputisayidi onse. Histone mapuloteni kudziunjikira owonjezera kuyang'anira zabwino zatsalira kwa amino acid. Iwo n'chongoletsa milandu zoipa okwana PO ₄ ^3- anions, m'gulu DNA lapansi. Mbali ina ya kapangidwe ka mapuloteni izi kwagona kuti pafupifupi ofanana mu zamoyo a ufumu wa zomera, nyama ndi bowa.

Popeza histones - mapuloteni ndi pachimake, iwo ndi chifukwa matabwa ake, mungathe kuchita njira kunachitika karyoplasm. Mwachitsanzo, zofunika kwambiri kwa galamafoniyo ndondomeko H1 peputayidi - histone mapuloteni kusunga nucleosomes ali mbali ya chromatin mwadongosolo, yaying'ono pachimake. Komanso, ngati kuwonongeka DNA loci, otchedwa pakati mamolekyulu peputayidi zosinthika ali nawo kukonza mbali imeneyi.

pachimake peputayidi

Iwo amaonetsera kapangidwe ka nucleosome, amene tichipeza amitundu inayi mamolekyulu otchedwa H2A, H2B ndi H3 ndi H4. The nucleosomes ndi awiri a mtundu uliwonse wa molekyulu, eg amenewa amatchedwa octamer. Molekyulu mapulotini deoxyribonucleic pachimake ndi mawonekedwe pakati pawo hydrophobic, hydrogen ndi nsinga covalent. Mapuloteni, histones ali pa maziko a nucleosome lapansi. iwo muli unstructured NC ndi ziwiri. mbali izi zigwirizana zatsalira 15-30 kwa amino acid ndi zedi mu ndondomeko epigenetic omwe amalamulira jini mawu. Kore histones chapakati gawo nucleosomes ndi yaing'ono maselo kulemera, m'madera awo, mosiyana ndi mchira mbali tizilumba tina zili hydrophobic monomers mapuloteni valine, proline, Lezina methionine.

Kafukufuku wa posachedwapa m'munda wa sayansi kuti zinachititsa kuti amanena pa malamulo histone. Mosiyana ndi malamulo kumtundu konsekonse chifukwa mitundu yonse ya moyo ma pa dziko lapansi, histone kachidindo ndi variable. Mawu amenewa amatanthauza kusintha mchira magawo a mapeputisayidi chifukwa cha acetylation anachita, methylation, phosphorylation. Zonsezi zimachititsa mankhwala zidzachitika pamaso pa maofesi multienzyme. Chifukwa njira ngati amuzolengedwa, ndi kusintha histones pachimake, ndi kusintha kumachitika akuti imene imachititsa kuti kulamulira zochita intranuclear zokhudza DNA: kukonzetsa galamafoniyo, kugawanika. Yekha mchikakamizo cha chromatin kusintha histone malamulo amaloŵamo kukonzanso, mwachitsanzo kusintha ma CD ake mu nucleosome ndi (akuwasindikiza kapena M'malo mwake, loosens).

linker mapuloteni

Histone H1 ali chromatin, chikugwirizana gawo lakunja la nucleosome ndi akuzisunga adalira supercoil deoxyribonucleic acid. fixation ake amapezeka pamalo tetramer ongokhala awiri peputayidi mamolekyulu H3 ndi H4 mamolekyulu awiri. The oimira gulu la ndi gulu la mbalame zokwawa maselo ofiira m'malo histone H1 linker mapuloteni anapeza H5 wina.

H1 peputayidi limapangidwa HMJB-ankalamulira - gawo structural, ndi zatsalira asidi pafupifupi 80 kwa amino. Iye ali pafupifupi chimodzimodzi zamoyo zambiri monga zomera, nyama ndi anthu. webusayitiyi kosamugonjera kusinthidwa ndi ndiwofatsa. Peputayidi N1 ali m'mitundu iwiri wa masanjidwe okhudza malo: a globule anakomoka ndipo zinachitika - mu mawonekedwe a ukachenjede. Yotsirizira kumachitika pamene kulankhulana sichitha C-osachiritsika m'chigawo cha histone ku madambwe DNA-amamanga. The linker peputayidi ndi kukhala wochitachita mu kukopera mfundo jini kuti mRNA molekyulu, ndi kudzikonda anawaonjezera kuwirikiza kawiri njira DNA, komanso yokonza owonongeka loci ake. Izi ndi ntchito zamoyo histones mu DNA lapansi.

Monga mapuloteni kupanga octamer

Mosiyana peputayidi H1, zina histones otchedwa ng'ombe, yodziwika ndi ductility zokwanira kupanga zosinthika mawonekedwe. Mwachitsanzo, H2A ali chiwerengero chapamwamba zosintha: H2AZH2AX MACROH2A. Amasiyana mzake:

• C-osachiritsika kwa amino asidi zinayendera.
• Location mu matupi athu ndi.

Mwachitsanzo, histone zosinthika H2ABbd cholukanalukana ndi chromatin imene DNA galamafoniyo amapezeka. MACROH2A peputayidi ali DNA interphase. maphunziro Cytological chinapezeka kuti histone H4 zosinthika mitundu akhala amadziŵika, koma akhoza kupanga ambiri kumangidwa covalent ndi mapuloteni ena otsata nucleosomes ndi octamer. Choncho, asayansi amakhulupirira kuti histones - gulu lapadera la mapulotini ali pafupifupi gawo la chromatin a mitundu yonse ma moyo.

Kodi kusunga zokhudza histones mu matupi athu ndi

Iwo akhoza kutsutsa kuti ng'ombe, ndi linker histone zosinthika ndiyotengera masango jini lofotokozedwa mu gawo kupanga ya selo mkombero moyo. Mwachitsanzo, kwa anthu otengera makhalidwe gulu lotchedwa HIST1 tichipeza majini 35 imapezeka chimodzi somatic awiri khromozomu. HIST2 limodzi limapangidwa majini asanu kabisidwe histones, ndi chromosomal malo awiri oyamba. Lilinso ndi locus HIST3 chikukhudza majini atatu. Mu awiri akhumi ndi chimodzi jini kabisidwe ndi histone H4. N'zochititsa chidwi majini pakati mapuloteni ndi introns, ndi majini a histones zosinthika M'malo mwake, ali iwo ndipo anabalalikira m'zigawo matupi athu ndi.

Kuti adzimvera, taona kuti histones wa - mapuloteni kumatanthauza kuika mwawo DNA mu phata, komanso mu ndondomeko ya malamulo, kukonza ndi galamafoniyo chichitike mu izo.