Phetolelo ea Protheine ho Synthesis ea Lisele
Phetolelo ea protheine ke e 'ngoe ea lits'ebetso tsa bohlokoa ka ho fetisisa bophelong ba sele. Ka phetolelo, tlhahisoleseling ea liphatsa tsa lefutso e bolokiloeng tatellanong ea nucleotide ea mRNA (messenger RNA) e fetoloa tatellano ea amino acid e etsang liprotheine. Liprotheine ka botsona li sebetsa e le likarolo tsa sebopeho, lienzyme, li-transporter tsa limolek'hule, esita le balaoli ba tlhahiso ea liphatsa tsa lefutso. Ntle le phetolelo e nepahetseng, lisele li ke ke tsa etsa mesebetsi ea metabolism, tsa hola, tsa lokisa, kapa tsa ikamahanya le tikoloho ea tsona.
Mehopolo ea Motheo: Ho tloha Liphatseng tsa Lefutso ho ea Liprotheineng
Ho baeloji ea limolek'hule , phallo ea tlhahisoleseling ea liphatsa tsa lefutso "DNA → RNA → Protheine" e tsejoa, hangata e bitsoa thuto ea mantlha. Phetolelo e kopitsa tlhahisoleseling ho tsoa ho DNA ho ea ho mRNA, ha phetolelo e fetolela mRNA ho ea ho protheine. Nakong ea phetolelo, "puo" ea li-nucleotide e fetoleloa ho ea ho "puo" ea li-amino acid. Mokhoa ona oa phetolelo o sebelisa khoutu ea liphatsa tsa lefutso ka mokhoa oa li-codon - lihlopha tsa metheo e meraro ea naetrojene ho mRNA - eo e 'ngoe le e 'ngoe ea tsona e ngolang amino acid e itseng kapa lets'oao la ho emisa.
Khoutu ea liphatsa tsa lefutso e batla e le ea bokahohle linthong tsohle tse phelang, ho bolelang hore li-codon tse tšoanang hangata li ngola li-amino acid tse tšoanang libaktheria , limela le batho. Ho feta moo, khoutu ea liphatsa tsa lefutso ea senyeha, ho bolelang hore amino acid e le 'ngoe e ka ngoloa ke li-codon tse fetang e le 'ngoe. Sena se thusa ho fokotsa tšusumetso ea liphetoho tse itseng, kaha phetoho ea nucleotide e le 'ngoe ha se kamehla e fellang ka phetoho ea amino acid.
Likarolo tse ka Sehloohong tsa Phetolelo
Ts'ebetso ea phetolelo e kenyelletsa likarolo tse 'maloa tsa bohlokoa:
1. mRNA (RNA ea lenģosa)
E sebetsa e le mohlala o jarang tlhahisoleseding e tswang ho DNA. Tatellano ya di-codon ho mRNA e etsa qeto ya tatellano ya amino acid diprotheineng.
2. Li-Ribosome
Li-ribosome ke "metjhini" e fetoletsweng e bopilweng ka rRNA (ribosomal RNA) le diprotheine tsa ribosomal. Li-ribosome di na le diyuniti tse pedi (tse nyane le tse kgolo) tse sebetsang mmoho ho bala mRNA le ho susumetsa ho thehwa ha dibofo tsa peptide.
3. tRNA (phetisetso ea RNA)
tRNA e sebetsa e le adaptara, e hokahanya codon ho mRNA le amino acid e tsamaellanang. TRNA ka 'ngoe e na le anticodon (metheo e meraro) e tsamaisanang le codon ea mRNA.
4. Li-amino acid
Ke thepa e tala bakeng sa ho haha liprotheine. Lisele li na le mekhoa ea ho netefatsa hore tRNA e na le li-amino acid tse nepahetseng.
5. Li-enzyme le lintlha tsa phetolelo
Tsena di kenyeletsa di-synthetase tsa aminoacyl-tRNA (tse "tjhajang" tRNA ka di-amino acid), hammoho le dintlha tse fapaneng tsa ho qala, ho lelefatsa le ho fedisa tse laolang bokgoni le ho nepahala ha tshebetso.
Mehato ea Phetolelo
Ka kakaretso, phetolelo e arotsoe ka mekhahlelo e meraro: ho qala, ho lelefatsa le ho fela. Mokhahlelo ka mong o hloka khokahano e rarahaneng pakeng tsa li-ribosome, tRNA, mRNA le liprotheine.
1. Qalo: Ho Qala Phetolelo
Ho qalisoa ho qala ha karoloana e nyane ea ribosome e tlama ho mRNA. Ho li-prokaryotes (mohlala, libaktheria), ribosome e lemoha tatellano e itseng ho mRNA e thusang ho fumana codon ea ho qala. Ho li-eukaryotes, karoloana e nyane ea ribosome hangata e tlama pheletsong ea 5' ea mRNA ebe e "scan" ho fihlela e fumana codon ea ho qala.
Codon e tloaelehileng haholo ea ho qala ke AUG, e leng khoutu ea amino acid methionine (formyl-methionine ka har'a prokaryotes). TRNA ea qalang e jara methionine 'me e tlama ho AUG sebakeng se holim'a ribosome se bitsoang P site (peptidyl site). Hang ha qalo e se e le teng, li-subunit tse kholo tsa ribosomal lia bokana ho etsa ribosome e sebetsang e itokiselitseng ho atolosa ketane ea polypeptide.
2. Ho Lelefatsa: Ho Lelefatsa Ketane ea Polypeptide
Ho lelefatsa ke mohato o ka sehloohong oa phetolelo moo li-amino acid li eketsoang ka bonngoe. Li-ribosome li na le libaka tse tharo tsa bohlokoa:
– Sebaka (sebaka sa aminoacyl): sebaka sa ho kena bakeng sa tRNA e ncha e jereng li-amino acid.
– Sebaka sa P (sebaka sa peptidyl): sebaka sa tRNA e jereng ketane e ntseng e hola ya polypeptide.
– Sebaka sa E (sebaka sa ho tsoa): sebaka seo tRNA e lokollotseng amino acid ea eona e tsoang ho sona.
Ts'ebetso ea ho lelefatsa e etsahala ka potoloho e pheta-phetoang:
1. TRNA e loketseng e kena sebakeng sa A ho latela papiso ya codon-anticodon.
2. Li-ribosome li susumetsa ho thehoa ha maqhama a peptide pakeng tsa li-amino acid sebakeng sa A le liketane tsa polypeptide sebakeng sa P. Mosebetsi ona oa catalytic o etsoa haholo-holo ke rRNA (ribozymes), eseng liprotheine ka botsona.
3. Ribosome ebe e fetisetsa codon e le 'ngoe ho mRNA (translocation). Ka lebaka leo, tRNA e jereng ketane ea polypeptide e tloha sebakeng sa A ho ea sebakeng sa P, ha tRNA e se nang letho e fallela sebakeng sa E ebe ea tsoa.
Potoloho ena e potlakile ebile e laoloa haholo. Ho nepahala ha phetolelo ho bolokoa ka ho khetha tRNA e nepahetseng le ts'ebetso ea enzyme aminoacyl-tRNA synthetase, e netefatsang ho kopanya ka nepo li-amino acid le tRNA.
3. Qetello: Ho Qetela Phetolelo
Phetolelo e fela ha ribosome e fihla ho stop codon ho mRNA. Li-stop codon tse tharo tse kholo ke UAA, UAG, le UGA. Li-codon tsena ha li na khoutu ea li-amino acid empa ho e-na le hoo li tsejoa ka termination factor (release factor). Termination factor e baka ho lokolloa ha ketane ea polypeptide ho tsoa ho tRNA sebakeng sa P, 'me ribosome e arohana ho ba li-subunit tse nyane le tse kholo tse ka sebelisoang hape bakeng sa phetolelo e latelang.
Kamora Phetolelo: Ho Mena le ho Fetola Protheine
Li-polypeptide tse sa tsoa thehoa ha li sebetse hang-hang. Liprotheine li tlameha ho mena ka sebopeho sa tsona se nepahetseng sa mahlakore a mararo. Ts'ebetso ena ea ho mena hangata e thusoa ke li-chaperone ho thibela ho mena kapa ho kopana hampe. Ho feta moo, liprotheine tse ngata li fetoloa ka mor'a phetolelo, joalo ka phosphorylation, glycosylation, ho thehoa ha disulfide bond, kapa ho arohana. Liphetoho tsena li ka fumana sebaka sa protheine ka har'a sele , botsitso, ts'ebetso ea enzymatic, kapa bokhoni ba ho sebelisana le liprotheine tse ling.
Liprotheine tse ling li boetse li na le matšoao a itseng a li lebisang ho li-organelle tse itseng. Mohlala, liprotheine tse reretsoeng ho ntša metsi kapa ho kopana ha lera hangata li hlahisoa ke li-ribosome tse hoketsoeng ho reticulum e se nang letho ebe li sebetsoa haholoanyane sesebelisoa sa Golgi.
Bohlokoa ba Taolo ea Phetolelo
Hase kamehla lisele li fetolelang li-mRNA tsohle ka ho lekana. Phetolelo ke ntlha ea bohlokoa ea taolo taolong ea tlhahiso ea liphatsa tsa lefutso , kaha e fetola tlhahisoleseling ka ho toba hore e be lihlahisoa tse sebetsang. Taolo ea phetolelo e ka susumetsoa ke ho fumaneha ha li-ribosome, li-tRNA, le li-amino acid, hammoho le boteng ba liprotheine tse tlamang mRNA kapa li-microRNA ho li-eukaryotes. Tlas'a maemo a sithabetsang, joalo ka khaello ea limatlafatsi kapa tšoaetso, lisele li ka fokotsa phetolelo ea lefats'e 'me tsa beha pele liprotheine tse itseng tse hlokahalang bakeng sa ho phela.
Tšusumetso ea Liphoso tsa Phetolelo le Kamano ea Tsona le Mafu
Liphoso tsa phetolelo li ka hlahisa liprotheine tse nang le sekoli tse sa sebetseng kapa tse chefo liseleng. Ho se tloaelehe ha li-ribosome, mabaka a phetolelo, kapa ho mena ha protheine ho ka baka mafu a fapaneng. Ho batho, ho bokellana ha liprotheine tse menahaneng hampe ho amahanngoa le mafu a methapo a kang a Alzheimer's le a Parkinson's. Ho sa le joalo, lithibela-mafu tse ngata li sebetsa ka ho shebana le li-ribosome tsa baktheria, ho thibela phetolelo, ho thibela libaktheria ho phela kapa ho ikatisa.
Qetello
Phetolelo ea protheine ke ts'ebetso ea mantlha tlhahisong ea sele e fetolelang khoutu ea liphatsa tsa lefutso ho mRNA ho li-polypeptide, ebe e ba liprotheine tse sebetsang. Ts'ebetso ena e kenyelletsa mosebetsi o hokahaneng oa li-ribosome, li-tRNA, li-amino acid, le lintlha tse fapaneng tsa taolo. Ka mekhahlelo ea ho qala, ho lelefatsa le ho felisa, lisele li netefatsa tlhahiso ea protheine e potlakileng empa e nepahetse. Kamora phetolelo, liprotheine li ntse li hloka ho menwa le ho fetoloa bakeng sa ts'ebetso e ntle ka ho fetisisa. Ka lebaka la karolo ea eona ea bohlokoa, tšitiso ea phetolelo e ka ba le litlamorao tse kholo bophelong ba 'mele' me ke sepheo sa bohlokoa bakeng sa nts'etsopele ea lithethefatsi le kalafo.
Haeba o batla, nka eketsa chate ea phallo ea ts'ebetso ea phetolelo (mofuta oa mongolo), mehlala ea li-codon le li-anticodon, kapa phapang phetolelong ea li-prokaryotes khahlanong le li-eukaryotes ka botlalo.
