Qhov Tseem Ceeb Qhov txawv - Base Excision Repair vs Nucleotide Excision Repair
DNA feem ntau raug kev puas tsuaj vim muaj ntau yam sab hauv thiab sab nraud. Txawm li cas los xij cellular kho tshuab tam sim ntawd thiab tas li kho qhov kev puas tsuaj ua ntej lawv hloov pauv lossis ua ntej lawv raug xa mus rau ntau tiam neeg. Muaj peb hom kev kho qhov txiav tawm hauv cov hlwb: nucleotide excision kho (NER), kev kho qhov kev txiav txim siab (BER), thiab kho DNA mismatch kho (MMR) los kho ib qho kev puas tsuaj DNA. Qhov sib txawv tseem ceeb ntawm kev kho lub hauv paus excision thiab nucleotide excision kho yog qhov kho qhov kev txiav tawm yog qhov kho yooj yim uas ua haujlwm hauv cov hlwb los kho ib qho nucleotide kev puas tsuaj los ntawm endogenously thaum nucleotide excision kho yog ib qho kev kho qhov nyuaj uas ua haujlwm hauv cov hlwb los kho qhov sib piv. loj dua, puas cheeb tsam tshwm sim exogenously.
Pab Excision Repair yog dab tsi?
Base excision kho yog qhov yooj yim tshaj plaws ntawm DNA kho qhov system uas lub hlwb muaj. Nws yog siv los kho cov kev puas tsuaj me me hauv DNA. DNA bases raug hloov vim deamination los yog alkylation. Thaum muaj kev puas tsuaj hauv paus, DNA glycosylase lees paub thiab ua kom lub hauv paus kev kho lub cev thiab rov qab los nrog kev pab los ntawm enzymes AP endonuclease, DNA polymerase, thiab DNA ligase. Cov kauj ruam hauv qab no koom nrog hauv BER system.
- Kev lees paub thiab tshem tawm ntawm qhov tsis raug lossis puas tsuaj los ntawm DNA glycosylase los tsim ib qho chaw abasic (chaw ntawm lub hauv paus poob -apiurinic lossis apyrimidinic sites).
- Abasic site incision los ntawm apurinic/apyrimidinic endonuclease
- Tshem tawm cov khoom qab zib ntxiv los ntawm lyase lossis phosphodiesterase
- Gap filling los ntawm DNA polymerase
- Kev sib khi ntawm lub npe los ntawm DNA ligase
Daim duab 01: Lub hauv paus excision kho txoj hauv kev
Nucleotide Excision Repair yog dab tsi?
Nucleotide Excision Repair (NER) yog ib qho tseem ceeb ntawm DNA kho qhov system hauv hlwb. Nws muaj peev xwm kho thiab hloov cov cheeb tsam puas mus txog 30 lub hauv paus nyob rau hauv ntev thiab nws yog qhia los ntawm lub undamaged template strand. Kev puas tsuaj DNA feem ntau tshwm sim vim hluav taws xob ultraviolet thiab NER tiv thaiv DNA los ntawm kev kho cov kev puas tsuaj tam sim ntawd ua ntej dhau los ua kev hloov pauv thiab dhau mus rau tiam tom ntej lossis ua rau muaj kab mob. NER tshwj xeeb muab kev tiv thaiv kev hloov pauv los ntawm kev tsis ncaj ncees los ntawm exogenous yam xws li ib puag ncig thiab tshuaj carcinogens. NER tau pom nyob rau hauv yuav luag txhua yam kab mob, thiab nws paub txog kev puas tsuaj uas ua rau muaj kev cuam tshuam loj hauv DNA helix.
Cov txheej txheem NER suav nrog kev ua ntawm ntau cov proteins xws li XPA, XPB, XPC, XPD, XPE, XPF, XPG, CSA, CSB, thiab lwm yam. Cov proteins no yog qhov tseem ceeb rau kev ua tiav ntawm cov txheej txheem kho, thiab qhov tsis xws luag hauv ib qho ntawm NER cov proteins yog qhov tseem ceeb thiab tuaj yeem ua rau cov kab mob tsis tshua muaj tshwm sim: xeroderma pigmentosum (XP), Cockayne syndrome (CS) thiab daim ntawv photosensitive ntawm cov plaub hau tsis zoo. trichothiodystrophy (TTD).
Daim duab 02: Nucleotide Excision Repair
Qhov txawv ntawm Base Excision Repair thiab Nucleotide Excision Repair yog dab tsi?
Base Excision Repair vs Nucleotide Excision Repair |
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| Base excision repair (BER) yog DNA kho qhov system tshwm sim hauv hlwb. | Nucleotide excision kho (NER) yog lwm hom kev kho DNA pom hauv hlwb. |
| Kev lees paub DNA Adducts | |
| BER kho kev puas tsuaj rau cov DNA me me. | NER kho cov DNA loj loj. |
| DNA Damages | |
| BER lees paub qhov kev puas tsuaj uas tsis ua rau muaj kev cuam tshuam loj rau DNA helix. | NER lees paub qhov kev puas tsuaj uas ua rau muaj kev cuam tshuam loj rau DNA helix. |
| Cas of DNA Damages | |
| BER kho qhov kev puas tsuaj los ntawm endogenous mutagens. | NER kho qhov kev puas tsuaj los ntawm exogenous mutagens. |
| BER yog qhov kho qhov nyuaj tshaj plaws | Nws nyuaj dua BER. |
| Nyob rau Proteins | |
| BER tsis xav tau lwm yam proteins. | NER xav tau ntau yam khoom lag luam, tshwj xeeb tshaj yog cov proteins, txhawm rau cais thaj chaw puas thiab tsis muaj kev puas tsuaj. |
| Kev tsim nyog | |
| BER yog tsim los kho ib qho kev puas tsuaj. | NER yog tsim los hloov cov cheeb tsam puas. |
Summary – Base Excision Repair vs Nucleotide Excision Repair
NER thiab BER yog ob hom kev kho DNA tshem tawm hauv cov hlwb. BER tuaj yeem kho qhov kev puas tsuaj me me los ntawm endogenously thaum NER tuaj yeem kho thaj chaw puas tsuaj txog 30 lub hauv paus khub ntev los ntawm feem ntau ntawm exogenously. BER txawv ntawm NER nyob rau hauv hom substrates tau lees paub thiab hauv qhov kev tshwm sim thawj zaug cleavage. BER tseem tuaj yeem paub txog kev puas tsuaj uas tsis yog tshwm sim los ntawm kev cuam tshuam loj hauv DNA helix thaum NER lees paub qhov cuam tshuam loj ntawm DNA helix. Qhov no yog qhov sib txawv ntawm kev kho lub hauv paus excision thiab nucleotide excision.
