Lub degeneracy ntawm lub caj code: tus tsim

Cov kev tshuaj ntsuam genetic code yog qhia raws li codons, ib tug system ntawm encoding cov lus qhia txog cov qauv ntawm cov nqaijrog, xam qhovkev nyob rau hauv tag nrho cov uas muaj sia nyob lub ntiaj teb. Decryption coj xyoo lawm, tab sis qhov tseeb hais tias nws tshwm sim, science yog to taub ze li ntawm ib xyoo pua. Versatility, tseem, unidirectional, thiab tshwj xeeb tshaj yog cov degeneracy ntawm lub caj code muaj lom tseem ceeb.

Keeb kwm ntawm discoveries

Qhov teeb meem ntawm encoding genetic ntaub ntawv yeej ib txwm tau tseem ceeb nyob rau hauv biology. Los ntawm matrix qauv ntawm cov kev tshuaj ntsuam genetic code, science loj es maj mam. Txij li thaum lub foundations ntawm J. Watson thiab Crick nyob rau hauv 1953. Lub ob helix qauv ntawm DNA nkag mus hauv ib theem ntawm kev daws rau ib tug code qauv nws tus kheej, uas sim hawm caij nyoog kev ntseeg nyob rau hauv lub hwj chim ntawm qhov. Lub linear qauv ntawm cov nqaijrog thiab DNA ntawm tib cov qauv rub lub xub ntiag ntawm lub caj code, cov xov xwm ntawm lub ob phau ntawv, tab sis kaw nrog txawv ntawv. Thiab yog hais tias cov tsiaj ntawv ntawm cov nqaijrog tau paub, lub DNA tias yog cov kev kawm ntawm txoj kev tshawb no ntawm biology, physics thiab kev kawm zauv.

Muaj yog tsis muaj yuav tsum tau piav qhia txog tag nrho cov kauj ruam nyob rau hauv kev daws ntawm no enigma. Direct xyaum ua tej yam, muaj pov thawj thiab paub tseeb hais tias hais tias ntawm DNA codons thiab cov amino acids ntawm cov protein yog ib tug ntshiab thiab zoo ib yam feem nyob rau hauv 1964 Charles Janowski thiab S. Brenner. Ib tug ntxiv - thaum lub sij hawm seev suab ntawm lub caj code nyob rau hauv vitro (nyob rau hauv vitro) siv cov tswv yim ntawm cov protein synthesis nyob rau hauv cell-free lug.

Nkaus decrypted code E. coli twb cai nyob rau hauv 1966, biologists nyob rau symposium ntawm khaub thuas caij nplooj ntoos hlav Chaw nres nkoj (TEB CHAWS USA). Ces kuv qhib lub redundancy (degeneracy) ntawm lub caj code. Yuav ua li cas no txhais tau tias, nws piav heev tsuas.

seev suab tseem

Tau deciphering lub roj ntsha code cov ntaub ntawv kuj yog ib qho ntawm feem ntau cov tseem ceeb ntawm lub xeem caug xyoo. Niaj hnub no, science tseem mus tshawb nyob rau hauv qhov tob lub mechanisms ntawm molecular encoding system thiab nws cov nta thiab ib tug overabundance ntawm tej yam tshwm sim, dab tsi yog hais nyob rau hauv cov cuab yeej ntawm tus degeneracy ntawm lub caj code. Ib tug cais txoj kev tshawb no ntawm lub lag luam - lub keeb kwm thiab evolution ntawm roj ntsha khoom coding system. Pov thawj txuas polynucleotides (DNA) thiab polypeptides (cov nqaijrog) muab impetus mus rau lub kev loj hlob ntawm molecular biology. Thiab hais tias, nyob rau hauv lem, biotechnology, bioengineering, discoveries nyob rau hauv yug me nyuam thiab tsob nroj cog.

Dogmas thiab cov kev cai

Tsev dogma ntawm molecular biology uas - cov ntaub ntawv yog kis los ntawm DNA rau cov tub txib RNA, thiab ces nrog nws nyob rau hauv lub protein. Nyob rau hauv kev coj rov qab kis tau tus mob yog tau los ntawm RNA rau DNA thiab RNA nyob rau lwm lub RNA.

Tab sis lub matrix los yog lub hauv paus ntawm DNA yeej ib txwm nyob. Thiab tag nrho cov lwm yam ntxwv yooj yim ntawm cov lus qhia hloov lwm lub tsev - ib tug rog xav txog ntawm qhov xwm ntawm cov kev hloov ntawm lub matrix. Namely, los ntawm kev ua kis tau tus mob mus rau lub synthesis ntawm lwm matrix molecules, uas yuav muab lub tu tub tu kiv ntawm cov qauv ntawm cov kev tshuaj ntsuam genetic ntaub ntawv.

kev tshuaj ntsuam genetic code

Kab coding qauv ntawm cov protein molecules los ntawm txoj kev complementary codons (triplets) nucleotides, uas tsuas 4 (adein, guanine, cytosine, thymine (uracil)), uas nthawv ua mus rau tsim ntawm lwm yam chains ntawm nucleotides. Cov tib tooj ntawm nucleotides thiab tshuaj complementarity - qhov no yog qhov tseem ceeb mob rau tej synthesis. Tab sis tsim ntawm ib tug protein molecule zoo txuam tus kom muaj nuj nqis thiab zoo tshaj ntawm cov monomers yog tsis (DNA nucleotides - protein amino acids). Qhov no yog lub ntuj raws roj ntsha code - cov ntaubntawv povthawj siv system nyob rau hauv lub sib lawv liag ntawm nucleotides (codons) cov amino acid ib theem zuj zus ntawm cov protein.

Caj code muaj ob peb zog:

• Triplet.
• Lub uniqueness.
• Orientation.
• Disjointness.
• Redundancy (degeneracy) ntawm lub caj code.
• Versatility.

Ntawm no yog ib nyuag lus piav qhia txog, ntawm lub lom tseem ceeb.

Triplet, laaj thiab muaj stoplights

Txhua yam ntawm 61 cov amino acids coj mus rau ib tug semantic t (triplet) nucleotides. Peb triplets tsis muaj ntaub ntawv hais txog cov amino acid thiab yog nres codons. Txhua nucleotide nyob rau hauv lub saw yog ib tug tswv cuab ntawm lub triplet, thiab tsis muaj nyob ntawm nws tus kheej. Thaum qhov kawg thiab qhov pib ntawm ib cov saw ntawm nucleotides coj mus rau ib tug tib protein, yog nres codons. Lawv pib los yog nres broadcasting (lub synthesis ntawm ib tug protein molecule).

Tseem, thiab ib-pointedness disjointness

Txhua codon (triplet) encodes tsuas yog ib qho amino acid. Txhua triplet yog ywj siab los ntawm thiab tsis sib tshooj nyob ib sab. Ib nucleotide yuav mus rau tsuas yog ib triplet nyob rau hauv cov saw hlau. Protein synthesis yog ib txwm nyob rau hauv ib tug kev taw qhia nkaus xwb, uas yog tshuaj nres codons.

Lub redundancy ntawm lub caj code

Txhua triplet ntawm nucleotides encodes ib amino acid. Ib tug tag nrho ntawm 64 nucleotides, 61 ntawm lawv - encoded amino acid (kev txiav txim zoo codon), thiab peb - meaningless, piv txwv li amino acid tsis encode (tsis txhob codons). Lub redundancy (degeneracy) ntawm lub caj code yog tias hloov tau nyob rau hauv txhua triplet - radical (ua rau cov amino acid hloov) thiab conservative (amino acids tsis hloov class). Nws yog ib qho yooj yim los mus laij hais tias yog ib tug triplet yuav tau ris 9 hloov (1, 2 thiab 3 txoj hauj lwm), txhua nucleotide yuav hloov los ntawm 4 - 1 = 3 rau lwm embodiment, tag nrho cov xov tooj uas tau nucleotide hloov yuav 61 rau 9 = 549.

Lub degeneracy ntawm lub caj code yog muaj nyob rau hauv lub fact tias 549 xaiv - nws yog ntau npaum li cas tshaj li tsim nyog rau zakodirovki ntaub ntawv hais txog 21 cov amino acids. Nyob rau hauv no cov ntaub ntawv ntawm kev hloov kev xaiv 549 23 lead mus rau tsim ntawm ib tug nres codon, 134 + 230 hloov - yog conservative hloov, thiab 162 - radical.

Txoj cai degeneracy thiab zam

Yog hais tias ob codons muaj ob tug zoo tib thawj nucleotide, cov seem nucleotides uas hais nrog ib chav kawm ntawv (purine los yog pyrimidine), cov ntaub ntawv lawv nqa tib amino acid. Qhov no yog feem ntau yog lub degeneracy los yog redundancy ntawm lub caj code. Ob tug zam - AUA thiab Uga - thawj encodes methionine, txawm hais tias yuav muaj mus isoleucine, thiab lub thib ob - ib tug nres codon, tab sis yuav tau encode tryptophan.

Lub ntsiab lus degeneracy thiab versatility

Cov ob thaj chaw ntawm lub caj code muaj lub siab tshaj plaws lom nqi. Tag nrho cov khoom teev saum toj no yog cov yam ntxwv ntawm cov kev tshuaj ntsuam genetic cov ntaub ntawv ntawm tag nrho cov ntaub ntawv uas muaj sia nyob rau ntawm peb lub ntiaj chaw.

Lub degeneracy ntawm lub caj code muaj ib qho kev coj tus nqi, raws li tus ua luam ntawm ib amino acid code. Nyob rau hauv tas li ntawd, qhov no txhais tau tias ib tug tseem ceeb yuav txo tau nyob rau hauv (degeneration) ntawm peb nucleotide nyob rau hauv ib tug codon. Xws li ib tug embodiment minimizes mutational txhab nyob rau hauv DNA, uas entail loj ua txhaum nyob rau hauv lub protein qauv. Qhov no yog ib tug tiv mechanism uas muaj sia nyob lub ntiaj teb.