Qhov sib txawv tseem ceeb ntawm Watson thiab Crick thiab Hoogsteen puag khub yog tias Watson thiab Crick lub hauv paus ua khub yog tus qauv uas piav qhia txog kev tsim cov hauv paus khub ntawm purines thiab pyrimidines. Lub caij no, Hoogsteen puag khub yog lwm txoj hauv kev ntawm kev tsim cov hauv paus khub uas cov purine siv qhov sib txawv ntawm kev hwm rau pyrimidine.
Y A nucleotide muaj peb yam: nitrogenous puag, pentose qab zib thiab phosphate pawg. Muaj tsib lub hauv paus nitrogenous sib txawv thiab ob lub suab thaj pentose koom nrog hauv cov qauv ntawm DNA thiab RNA. Thaum cov nucleotides tsim cov nucleotide ib ntus, cov hauv paus ntxiv, xws li purines lossis pyrimidines, tsim hydrogen bonds ntawm lawv. Qhov no yog hu ua base pairing. Yog li ntawd, lub hauv paus khub yog tsim los ntawm kev koom nrog ob lub hauv paus nitrogenous los ntawm hydrogen bonds. Watson thiab Crick lub hauv paus kev sib koom ua ke yog qhov classic lossis tus qauv, thaum Hoogsteen puag ua khub yog lwm txoj hauv kev ntawm kev ua khub hauv paus.
Watson thiab Crick Base Pairing yog dab tsi?
Watson thiab Crick lub hauv paus khub yog tus qauv qauv uas piav qhia txog kev sib koom ua ke ntawm nitrogenous hauv paus hauv nucleotides. James Watson thiab Francis Crick, hauv xyoo 1953, tau piav qhia txog txoj hauv kev no, uas ua rau cov txheej txheem ob npaug ntawm DNA. Raws li Watson thiab Crick puag ua khub, adenine tsim hydrogen bonds nrog thymine hauv DNA thiab nrog uracil hauv RNA. Ntxiv mus, guanine tsim hydrogen bonds nrog cytosine hauv DNA thiab RNA.
Daim duab 01: Watson thiab Crick Base Pairing
Muaj peb daim ntawv cog lus hydrogen ntawm G thiab C thaum muaj ob daim ntawv cog lus hydrogen ntawm A thiab T. Cov khub hauv paus no tso cai rau DNA helix tswj nws cov qauv helical tsis tu ncua. Feem ntau cov nucleotide sequences (60%) muaj Watson thiab Crick puag khub uas ruaj khov ntawm nruab nrab pH.
Hoogsteen Base Pairing yog dab tsi?
Hoogsteen puag khub yog lwm txoj hauv kev ntawm kev tsim cov hauv paus khub hauv nucleic acids. Qhov no tau piav qhia thawj zaug los ntawm American biochemist Karst Hoogsteen xyoo 1963. Hoogsteen puag khub zoo ib yam li Watson thiab Crick puag khub. Lawv tshwm sim ntawm adenine (A) thiab thymine (T), thiab guanine (G) thiab cytosine (C). Tab sis purine yuav siv sij hawm sib txawv nrog kev hwm rau pyrimidine. Nyob rau hauv A thiab T puag khub, lub adenine yog rotated nyob rau hauv 180 0txog glycosidic daim ntawv cog lus, tso cai rau lwm txoj kev hydrogen bonding tswvyim. Ib yam li ntawd, hauv G thiab C khub, guanine yog tig 180 ° txog glycosidic daim ntawv cog lus. Ntxiv mus, lub kaum sab xis ntawm glycosidic bonds loj dua hauv Hoogsteen puag khub. Dhau li ntawd, tsim ntawm Hoogsteen puag khub tsis ruaj khov ntawm nruab nrab pH.
Daim duab 02: Watson thiab Crick Base Pairing vs Hoogsteen Base Pairing
Hoogsteen puag khub yog non-canonical puag khub uas ua rau cov nucleotide sequences tsis ruaj khov dua tus qauv puag khub. Ntxiv mus, lawv tuaj yeem ua rau muaj kev cuam tshuam ntawm DNA ob chav helix. Txawm hais tias Hoogsteen lub hauv paus khub tshwm sim ib txwm muaj, lawv tsawg heev.
Dab tsi zoo sib xws ntawm Watson thiab Crick thiab Hoogsteen Base Pairing?
- Watson thiab Crick thiab Hoogsteen puag ua khub yog ob txoj hauv kev los piav qhia txog kev tsim cov hauv paus khub hauv nucleic acids.
- Ob leeg tshwm sim hauv DNA.
- Ntxiv mus, lawv muaj nyob rau hauv kev sib npaug nrog ib leeg.
- paj khub zoo sib xws hauv ob txoj hauv kev.
Qhov txawv ntawm Watson thiab Crick thiab Hoogsteen Base Pairing yog dab tsi?
Watson thiab Crick puag ua khub yog tus txheej txheem uas piav qhia txog kev tsim cov hauv paus khub ntawm purines thiab pyrimidines. Ntawm qhov tod tes, Hoogsteen puag khub yog lwm txoj hauv kev ntawm kev tsim cov hauv paus khub uas cov purine siv qhov sib txawv nrog kev hwm rau pyrimidine. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm Watson thiab Crick thiab Hoogsteen puag khub. Watson thiab Crick puag khub tau piav qhia los ntawm James Watson thiab Francis Crick hauv xyoo 1953 thaum Hoogsteen puag khub tau piav qhia los ntawm Karst Hoogsteen hauv 1963. Ntxiv mus, Watson thiab Crick puag khub ruaj khov thaum Hoogsteen puag khub feem ntau tsis ruaj khov.
Cov hauv qab no qhia txog qhov sib txawv ntawm Watson thiab Crick thiab Hoogsteen puag ua khub.
Summary – Watson thiab Crick vs Hoogsteen Base Pairing
Watson thiab Crick puag khub thiab Hoogsteen puag khub yog ob hom kev piav qhia txog kev tsim cov nitrogenous hauv paus hauv nucleotide sequences. Hauv Hoogsteen puag khub, lub hauv paus purine siv qhov sib txawv nrog kev hwm rau pyrimidine puag. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm Watson thiab Crick thiab Hoogsteen puag khub. Ntxiv mus, Watson thiab Crick puag khub ruaj khov DNA ob chav helix thaum Hoogsteen puag khub ua rau lub helix tsis ruaj khov. Txawm li cas los xij, ob qho tib si hauv paus khub tshwm sim ib txwm muaj, thiab lawv muaj nyob hauv qhov sib npaug nrog ib leeg.
