Nokuwohloka ikhodi zofuzo: izisekelo

Ikhodi zofuzo sivezwe njengoba codons, isimiso ngamakhodi ulwazi mayelana nesakhiwo amaprotheni, esivela kuzo zonke izinto eziphilayo emhlabeni. Ukususa ukubethela kungathatha amashumi eminyaka, kodwa iqiniso ukuthi ukhona, isayensi siqondwa Kwacishe kwaphela ikhulu leminyaka. Yizinhlobonhlobo, ngokucacile, unidirectional, futhi zofuzo ikakhulukazi ikhodi nokuwohloka anencazelo begazi.

Umlando eminingi etholakale

Inkinga ikhodi ukwaziswa kwezakhi zofuzo bekulokhu ukhiye eziphilayo njalo. Ngu isakhiwo matrix isimiso sezakhi zofuzo, isayensi wathuthuka kunalokho kancane. Kusukela kwatholakala J. Watson Crick ngo-1953 I double Helix isakhiwo DNA Ufake isigaba ukusombulula isakhiwo ikhodi ngokwayo, okuyinto eyenza inkolelo nobukhulu bemvelo. Isakhiwo komugqa amaprotheni DNA sakhiwo lesifanako ibeke khona isimiso sezakhi zofuzo, izincwadi phakathi nemibhalo emibili, kodwa aqoshiwe kumagama ahlukahlukene. Futhi uma zamagama amaprotheni yaziwa, amamaki DNA zaba isihloko ukutadisha biology, i-physics kanye mathematics.

Asikho isidingo ukuchaza zonke izinyathelo e isixazululo sale imfihlakalo. experiment okuqondile, waba futhi waqinisekisa ukuthi phakathi codons DNA futhi ama-amino acid amaprotheni kukhona wokuziphatha oqondile futhi ngokulandelana labetibambile ngo-1964 Charles Janowski futhi S. Brenner. Esinye - ngesikhathi emagama ikhodi zofuzo ngaphandle kwesibeletho (ngaphandle kwesibeletho) ngekusebentisa emasu wamaprotheni zamagama e izakhiwo cell-mahhala.

Ngokugcwele uguqulwa ikhodi E. coli waziswa ngamhla zi-1966, izazi zezinto eziphilayo at sochungechunge at Cold Spring Sikhungo Semikhumbi (USA). Khona-ke ngavula komsebenzi (nokuwohloka) ikhodi zofuzo. Yini lokhu kusho ukuthini, ezazichazwa impela nje.

emagama uyaqhubeka

Ukuthola efunda okwakubhalwe kulowo mbhalo lezinceku idatha ikhodi isibe omunye izenzakalo ezibaluleke kakhulu kulelo khulu leminyaka eledlule. Namuhla, isayensi uyaqhubeka ukuhlola ukujula imiklamo of yamangqamuzana wekhodi uhlelo kanye nezici zayo kanye overabundance zezibonakaliso, lokho lubonakala impahla nokuwohloka ikhodi zofuzo. Ucwaningo ehlukile umkhakha - umsuka kanye kwemvelo lezinceku impahla esephepheni uhlelo. Ubufakazi ngokuxhumanisa polynucleotides (DNA) kanye polypeptides (amaprotheni) anikeza ugqozi ukuthuthukiswa we-molecular biology. Futhi lokho, i-biotechnology, Bioengineering, nokwatholakala in zizalela batshale ezikhulayo.

Nezimfundiso kanye nemithetho

Ikhaya umbhedesho we-molecular biology - ulwazi budluliselwe kusuka DNA isithunywa RNA, bese naye ku amaprotheni. Kolunye uhlangothi yokudlulisela kungenzeka kusukela RNA ku-DNA futhi RNA kwamanye RNA.

Kodwa matrix noma ngesisekelo DNA njalo uhlala. Futhi zonke ezinye izici eziyisisekelo yokudlulisa ulwazi - kukhombisa ubunjalo ukudluliselwa matrix. Okungukuthi, ngokwenza ukudlulisela synthesis namanye amangqamuzana-matrix, okuzoba kabusha isakhiwo ukwaziswa kwezakhi zofuzo.

isimiso sezakhi zofuzo

Line esephepheni isakhiwo wamaprotheni molecule esebenzisa codons aphelele (ezintathu) ama-nucleotide, okuyinto kuphela 4 (adein, i-guanine ne-cytosine, ne-thymine (uracil)), okuyinto angesabi kuholela ekwakhekeni yezinye amaketango nucleotide. Inani elifanayo futhi complementarity amakhemikhali nucleotide - lena isimo esiyinhloko zamagama ezifana. Kodwa kumiswa izinga amaprotheni-molecule afanayo zokwandisa nokuthuthukisa ikhwalithi monomers akuyona (nucleotide DNA - amaprotheni amino acid). Lona yemvelo lezinceku ikhodi - Ukuqoshwa uhlelo ukulandelana nucleotide (codons) Amino acid ukulandelana amaprotheni.

isimiso sezakhi zofuzo anezakhi eziningana:

• Triplet.
• Ohlukile.
• Ukuma.
• Disjointness.
• Redundancy (nokuwohloka) ikhodi zofuzo.
• Ezihlukahlukene zokusisebenzisa.

Nansi incazelo emfushane, ukugxila ukubaluleka kwezinto eziphilayo.

Triplet, lenqubekela phambili kanye nokusebenza ukutholakala stoplights

Ngamunye 61 amino acid elihambisana t semantic (triplet) ama-nucleotide. ezintathu ezintathu ningathwali ulwazi mayelana acid acid futhi codons stop. Ngamunye nucleotide esikuziphathimandla eyilungu le triplet, futhi alikho ngokwalo. Ekupheleni nokuqala uchungechunge nucleotide elihambisana iprotheni olulodwa, kukhona codons stop. Bathoma noma stop yezokusakaza (synthesis molecule amaprotheni).

Ngokucacile, futhi omunye-pointedness disjointness

codon ngamunye (triplet) buqonda eyodwa kuphela-amino acid. triplet ngayinye izimele futhi akusho kuyendlulela eduze. Omunye nucleotide kungaba sochungechungeni olulodwa triplet lapha. Amaphrotheni zamagama uhlale kwelinye direction, esiyinyama esilawulwa stop codons.

I komsebenzi we isimiso sezakhi zofuzo

Ngamunye triplet ka-nucleotide buqonda eyodwa acid acid. Linani selilonkhe lebantfu labange-64 ama-nucleotide, 61 babo - okubhalwe acid acid (umuzwa codon), futhi abathathu - lutho, ie-amino acid akusho encode (ayeke codons). I komsebenzi (nokuwohloka) ikhodi zofuzo ukuthi izisusi ingenziwa triplet ngamunye - olukhulu (okuholela acid acid esikhundleni) kanye olandelanayo (ama-amino acid musa ukushintsha ekilasini). Kulula ukubala ukuthi uma triplet theka 9 izisusi (1, 2 no 3 isikhundla), nucleotide ngayinye ungayithola enye by 4 - 1 = 3 omunye samuntu, inani eliphelele kungenzeka nucleotide izisusi kuyoba 61 kuya ku-9 = 549.

Nokuwohloka ikhodi zofuzo iboniswa iqiniso lokuthi 549 ongakhetha - ke kungaphezu ezidingekayo ukuze uthole ulwazi zakodirovki mayelana 21 amino acid. Kulokhu ongakhetha esikhundleni 549 23 kuholela ekwakhekeni codon stop, 134 + 230 esikhundleni - kukhona izisusi ngoludala, futhi 162 - olukhulu.

Ukubusa nokuwohloka kanye okuhlukile

Uma codons ezimbili kukhona ezimbili ezifanayo nucleotide lokuqala, nucleotide esisele betfulelwa ekilasini (purine noma pyrimidine), ulwazi Zithwala okufanayo acid acid. Lokhu ngokuvamile nokuwohloka noma komsebenzi we isimiso sezakhi zofuzo. ngaphandle kwababili - AUA futhi UGA - lokuqala buqonda methionine, nakuba kuzofuneka ukuthi isoleucine, kanti eyesibili - a codon stop, kodwa kuzofuneka ukuthi encode tryptophan.

Okusho nokuwohloka nezindlela ezihlukahlukene zokusisebenzisa

ezimbili Lezi izakhiwo isimiso sezakhi zofuzo babe okubaluleke kakhulu begazi. Zonke izakhiwo ezibalwe ngenhla sici ulwazi zofuzo zonke izinhlobo eziphilayo eplanethini yethu.

Nokuwohloka ikhodi zofuzo inenani oluhambelana, njengoba ukuphindaphindeka okuphindiwe nekhowudi acid acid. Ngaphezu kwalokho, lokhu kusho ukuncipha eziphawulekayo (ukonakala) we nucleotide wesithathu codon. i samuntu okunjalo kwenza intuthwane izilonda mutational e-DNA, okuyinto kwakuhilelani nokwephula e isakhiwo amaprotheni. Lena indlela zokuzivikela eziphilayo emhlabeni.