Qhov Tseem Ceeb Qhov txawv - Hom I vs Hom II Kev txwv Enzyme
Ib txwv enzyme, feem ntau hu ua kev txwv endonuclease, muaj peev xwm txiav DNA molecules rau hauv me me. Cov txheej txheem cleaving no tshwm sim nyob ze lossis ntawm qhov chaw paub tshwj xeeb ntawm DNA molecule hu ua qhov chaw txwv. Ib qhov chaw lees paub feem ntau yog tsim los ntawm 4-8 lub hauv paus khub. Nyob ntawm qhov chaw ntawm cleavage, txwv enzymes tuaj yeem yog plaub hom sib txawv; Hom I, Hom II, Hom III thiab Hom IV. Ntxiv rau qhov chaw ntawm cleavage, yam xws li muaj pes tsawg leeg, qhov yuav tsum tau ntawm co yam tseem ceeb thiab cov xwm txheej ntawm lub hom phiaj sib lawv liag tau muab rau hauv kev txiav txim siab thaum sib txawv txwv cov enzymes hauv plaub pawg. Thaum lub sij hawm cleavage ntawm DNA molecule, qhov chaw cleaving tuaj yeem nyob ntawm qhov chaw txwv nws tus kheej lossis nyob deb ntawm qhov chaw txwv. Thaum lub sij hawm tus txheej txheem ntawm cleavage ntawm DNA, cov kev txwv enzymes tsim ob incisions los ntawm txhua lub qab zib phosphate qaum qaum nyob rau hauv ob helix ntawm DNA. Kev txwv enzymes feem ntau pom muaj nyob hauv Achaea thiab cov kab mob. Lawv siv cov enzymes no ua cov txheej txheem tiv thaiv tiv thaiv cov kab mob invading. Cov kev txwv enzymes tshem tawm txawv teb chaws (pathogenic) DNA, tab sis tsis yog nws tus kheej DNA. Nws tus kheej DNA tau txais kev tiv thaiv los ntawm ib qho enzyme hu ua methyltransferase uas ua rau kev hloov kho hauv tus tswv DNA thiab tiv thaiv kev tawg. Hom I txwv enzyme muaj qhov chaw cleaving uas nyob deb ntawm qhov chaw lees paub. Hom II txwv enzymes cleave nyob rau hauv qhov chaw paub nws tus kheej los yog nyob ze rau nws. Qhov no yog qhov sib txawv tseem ceeb ntawm Hom I thiab Hom II txwv enzyme.
Yuav ua li cas yog Hom I txwv Enzyme?
Hom I txwv enzymes yog pentameric proteins uas muaj peb lub subunits: txwv subunit, methylation subunit, thiab DNA sequence recognition subunit. Cov subunits no tsis zoo ib yam. Lawv tau pib pom nyob rau hauv ob hom sib txawv ntawm Escherichia coli. Qhov chaw cleavage ntawm cov enzymes txwv tsis pub muaj nyob ntawm cov ntsiab lus sib txawv, feem ntau 1000 lub hauv paus khub deb ntawm qhov chaw lees paub. Cov kev txwv enzymes no xav tau ATP, Mg2+ thiab S-adenosyl-L-methionine rau nws ua kom. Hom I txwv enzymes muaj ob qho tib si methylase thiab txwv kev ua ub no. Cov kab mob siv cov enzymes txwv tsis pub ua cov txheej txheem tiv thaiv cellular los ntawm cov kab mob invading. Kev txwv enzymes tshem tawm cov kab mob DNA thiab rhuav tshem lawv. Tab sis txhawm rau tiv thaiv kev sib cais ntawm nws tus kheej lub tswv yim DNA, hom I txwv enzyme muab kev tiv thaiv methylation. Qhov no hloov pauv tus tswv tsev DNA thiab tiv thaiv kev tawg. Txawm hais tias cov enzymes txwv tsis pub muaj biochemical tseem ceeb, lawv tsis tau siv dav vim lawv tsis muab cov kev txwv tsis pub sib cais lossis cov qauv gel khi.
Yuav ua li cas hom II txwv Enzymes?
Hom II txwv enzymes muaj ob lub subunits zoo tib yam hauv lawv cov qauv. Homodimers yog tsim los ntawm hom II txwv enzymes nrog rau qhov chaw paub. Cov chaw lees paub feem ntau yog palindromic thiab tsis sib faib. Nws muaj qhov ntev ntawm 4-8 lub hauv paus khub. Tsis zoo li hom I, Hom II txwv enzyme qhov chaw cleavage muaj nyob ntawm qhov chaw lees paub lossis tam sim no nyob ze rau qhov chaw lees paub.
Daim duab 02: Hom II txwv tsis pub muaj cov enzymes
Cov kev txwv enzymes no yog biochemically tseem ceeb thiab muaj dav hauv kev lag luam. Rau nws txoj kev ua kom muaj zog, nws tsuas yog xav tau Mg2+ Nws tsis muaj kev ua haujlwm methylation thiab tsuas yog muab kev ua haujlwm ntawm kev txwv. Cov kev txwv enzymes khi rau DNA molecules ua homodimers thiab muaj peev xwm paub txog cov kab ke DNA sib luag zoo li asymmetrical sequences.
Dab tsi yog qhov zoo sib xws ntawm Hom I thiab Hom II Kev txwv Enzymes?
- Hom I thiab Hom II txwv enzymes yog hom enzymes yog txwv endonucleases uas koom nrog hauv kev sib cais ntawm DNA molecules rau hauv me me.
- Ob leeg muaj txiaj ntsig hauv Molecular biological techniques.
Dab tsi yog qhov txawv ntawm Hom I thiab Hom II Kev txwv Enzyme?
Type I vs Type II Restriction Enzyme |
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| Type I txwv enzyme yog DNA txwv enzyme uas cleaves DNA ntawm qhov chaw random deb ntawm nws qhov chaw lees paub. | Type II txwv enzyme yog DNA txwv enzyme uas cleaves DNA ntawm txoj haujlwm tau hais nyob ze lossis hauv qhov chaw lees paub. |
| Type I txwv enzyme yog ib qho enzyme complex uas yog tsim los ntawm peb (03) nonidentical sub units. | Hom II txwv enzyme yog ib qho yooj yim enzyme uas yog tsim los ntawm ob lub subunits zoo tib yam. |
| Molecular Luj | |
| Hom I txwv enzyme hnyav 400, 000 d altons. | Hom II txwv enzyme muaj qhov hnyav ntawm 20,000 - 100,000 d altons. |
| Aluminence of CasteVage | |
| Cleavage sequence tsis yog tshwj xeeb hauv hom I txwv enzyme. | Hom II txwv enzyme muaj qhov tshwj xeeb ntawm cleavage. |
| site ntawm cleavage | |
| Qhov chaw ntawm kev sib cais yog 1000 nucleotides deb ntawm qhov chaw lees paub hauv hom I txwv enzymes. | Qhov chaw ntawm kev sib cais yog nyob ntawm qhov chaw lees paub lossis tsis pub dhau qhov deb ntawm qhov chaw lees paub hauv hom II txwv enzyme. |
| Cefactors for Activation | |
| Type I txwv enzyme xav tau ATP, Mg2+ thiab S-adenosyl-L-methionine rau nws qhov ua kom. | Tsuas yog Mg2+ yuav tsum tau qhib hom II txwv enzyme. |
| Methylation Activity | |
| Hom I enzyme muab kev tiv thaiv DNA los ntawm methylation. | Tsis muaj kev ua haujlwm methylation hauv Hom II txwv enzymes. |
| Kev ua haujlwm ntawm Enzyme | |
| Type I txwv enzyme muab ob qho tib si endonuclease (txheej txheem) thiab cov dej num methylation. | Hom II txwv enzyme tsuas yog txwv kev ua haujlwm xwb. |
| Examples | |
| EcoK, EcoB | Hind II, EcoRI |
Summary – Hom I vs Hom II txwv Enzyme
Kev txwv enzymes raug xa mus rau cov txiab lom uas txiav DNA molecules rau hauv cov khoom me. Kev txwv cov enzymes tau muab faib ua 04 pawg sib txawv raws li qhov chaw ntawm qhov chaw cleavage nrog rau qhov chaw lees paub, co yam tam sim no, muaj pes tsawg leeg thiab cov xwm txheej ntawm lub hom phiaj sib lawv liag. Rau nws txoj kev ua haujlwm, Hom I txwv cov enzymes xav tau ATP, Mg2+, thiab S-adenosyl-L-methionine. Qhov chaw cleavage ntawm hom I txwv enzyme yog tam sim no feem ntau 1000 puag khub deb ntawm qhov chaw lees paub thiab muab kev tiv thaiv methylase rau DNA. Hom II txwv enzymes tsuas yog xav tau Mg2+rau nws ua kom. Qhov chaw cleavage tam sim no nyob ntawm qhov chaw lees paub lossis ze rau nws. Nws tsis muaj kev ua haujlwm methylation thiab muaj dav muag muag. Qhov no yog qhov txawv ntawm hom I txwv enzyme thiab hom II txwv enzyme.
Download PDF Version of Type I vs Type II Restriction Enzyme
Koj tuaj yeem rub tawm PDF version ntawm kab lus no thiab siv nws rau offline hom phiaj raws li daim ntawv ceeb toom. Thov rub tawm PDF version ntawm no Qhov txawv Ntawm Hom I thiab Hom II Kev txwv Enzyme.
