Ka DNA lātoma: na pae o mall hui

DNA lātoma - he polynucleotide lātoma huahelu i mea eha deoxyribonucleotide (dAMF, dGMP, dCMP a me dTMP). Ka lākiō o ke kaʻina o kēia mau nucleotides i loko o ka DNA o kekahi meaola i okoa. Ma waho o ka papa kuhikuhiE nitrogenous kumu ma ka DNA i kekahi'ē aʻe nīnūnē kumu deoxyribonucleotides me ka 5-methylcytosine, 5-oksimetiltsitozin, 6-methylaminopurine.

Once ua he manawa kūpono no ka hoʻohana i ke ano o ka X-Ray crystallography e noiʻi i liluwelo macromolecules, a loaa hemolele X-Ray, ka mea, ua hiki ke loaʻa mai i ka hakakino 'ole o ka DNA. I aku la o iaoiaeii ua ma muli o ka mea i ka laau o laua X-kukuna hana 'ia ma luna o ka mea pōaka huhui waina a lākou nā'ātoma,' ano apau loa i ka diffraction kumu, aʻano nui hilinaʻi nui ma luna o ka'ātoma kaumaha o na nā'ātoma, a me kā lākou wahi ma ka lewa. Ma na 40s o ka hope ke kenekulia, ke kumumanaʻo o ka ekolu-dimensional 'ole o ka DNA lātoma i ua waiho mua. U. Astbury hoao i ka deoxyribonucleicʻakika mea he noae o superimposed palahalaha nucleotides.

Ke iniiaiie 'ole o ka DNA lātoma

Ma lalo o ka iniiaiie 'ole o nukelea nāʻakika, ua manaoia he kaʻina o nucleotides i loko o ka hoʻoponoponoʻana o Kamehameha polynucleotide DNA kaula. Nucleotides i ua hoʻopili pū ma ka phosphodiester makaukau na kaula paa a pau i hanaʻia ma waena o ka OH pae ma ka 5 kulana o kekahi nucleotide a deoxyribose ka OH-pae i hoʻomoana 3 o kekahi pentose.

Ke liluwelo waiwai o ka nukeleaʻakika hiʻohiʻona nānā 'ia e ka qualitative, a ma ka nucleotide kaʻina o ka polynucleotide kaula.

Ke nucleotide haku mele 'ana o ka DNA mai meaola o okoa taxonomic pūʻulu mea kekahi, a ua nānā' ia e ka lākiō (G + C) / (A + T). E ho ohana ololi specificity i manao ma ke degere o ka heterogeneity o ka nucleotide haku mele 'ana o ka DNA mai meaola o kekahi kumu. Pela, i kiekie mea kanu a me nā holoholona hiʻohiʻona (G + C) / (A + T) loli aʻe iki, a mai ka waiwai i oi aku mamua 1. No ka microorganisms specificity kaʻi lau waiwai loli aʻe kaiāulu - mai 0,35 a 2,70. Eia naʻe, somatic keena o ka laha 'o DNA pihaʻi me na ia nucleotide haku mele' ana, oa. E. mākou ke olelo aku i ka maʻiʻo o ka GC hui o nā kumu o ka DNA o kekahi? Ueo i'ālike.

Hoʻoholo 'ana o heterogeneity o ka nucleotide haku mele' ana o ka DNA i ka uku o ka specificity, aole ia e haawi 'ike e pili ana i kona liluwelo waiwai. Nei, aie i ka mea okoa i ho'ākāka 'nucleotide kaʻina i loko o ka polynucleotide kaulahao mau apana. Kēia 'o ia hoʻi i ka aaiaoe ike encoded ma ka DNA nā lātoma i loko o kekahi mau' kaʻina o kona monomeric naehana.

A DNA lātoma ec nucleotide kaʻina manao ia no ka hoʻomaka a me ka hoopau ana i keʻano o ka hanaʻana o ka hoʻololi kemikala o DNA (replication) o ka RNA hoʻololi kemikala (Ekolu a) kumuʻiʻo hoʻololi kemikala (unuhi). Aia i nucleotide kaʻina, e hookauwa aku, e nakinaki kekahi ho'ā 'ia paha, a inhibitory hoʻokonukonu nā lātoma, e like me nucleotide kaʻina i mai i lawe i kekahi aaiaoe ike. Aia i kekahi Hoʻololi 'o ka mahinaʻai, a hoomalu nae lakou i na nā lātoma mai nucleases.

Ka pilikia o ka nucleotide kaʻina o DNA i ole i ua loa Wehewehe i nā hāʻina. Hoʻoholo 'ana o nucleotide kaʻina o nukelea nāʻakika ka manawa-e hoopau ana i ke kaʻina hana, a ua hoakaka no ka hoʻohana o nuclease cleavage iaoia ho'ākāka nā lātoma i mau hakina. I ka lā, i ka piha nucleotide kaʻina o ka nitrogenous kumu hoʻokumu no ka hapanui o tRNA kekahi kumu.

Ka DNA lātoma: haumāna 'ole

Watson a me Crick ua papahana he kumu hoʻohālike o ka waʻa helix o deoxyribonucleicʻakika. E like me ia i kēia ÷, ka polynucleotide kaula hiloʻelua i ka wili hoʻokahi kekahi i kekahi, ma ia ho okumu i ke ano o ka helix.

Nitrogenous kumu ka mea, e aia i loko o ka 'ole, a me ka phosphodiester iwi kuamoo - waho.

Ka DNA lātoma: tertiary 'ole

Ka laina DNA i loko o ka halepaahao i ka kinona o ka elongated lātoma, ka mea, ua pūʻolo helu ia ma ka olelo hoopomaikai 'ole a me ka lawe i wale 1/5 o ka halepaahao ka leo. No ka laʻana, ka DNA o kanaka chromosome lōʻihi o 8 knm, a ua piha no laila, e fits i loko o ka chromosome me ka lōʻihi o ka 5 HI. Oia stacking mea hiki no i ke alo o ka helical DNA hale. Mai keia ka mea, penei i ka waʻa-ili DNA helix ma ka makahiki hiki e hou stacking he maopopo tertiary 'ole - superhelix. Supercoiled conformation o ka DNA ano o na chromosomes o kiekie meaola. Oia tertiary 'ole stabilized e covalent makaukau na kaula paa e'aminoʻakika residues mea e i na nā polokina e hana i ka nucleoprotein luna' (chromatin). Nolaila, o ka DNA o eukaryotic keena pili i nā polokinaʻano nui walaʻauʻana ano - histones, e like meʻakika nā polokina, a fosfoproteidami.