Lac vs Trp Operon
Operon yog qhov tshwj xeeb gene alignment hauv prokaryotes. Nyob rau hauv ib lub operon, nws aligns tag nrho cov noob xav tau rau ib tug tshwj xeeb muaj nuj nqi. Lub koom haum no tso cai rau ib tus neeg txhawb nqa los qhib, deactivate, thiab tswj tag nrho cov noob uas koom nrog hauv ib qho haujlwm tshwj xeeb. Vim qhov xwm txheej no, operon yog hu ua lub luag haujlwm ntawm prokaryotic gene qhia. Lac operon thiab Trp operon yog ob tus neeg ua haujlwm pom hauv E.coli kab mob genome, thiab hauv ntau lwm cov kab mob. Cov neeg ua haujlwm no tswj cov haujlwm sib txawv. Operon yog chav ua haujlwm ntawm prokaryotic gene qhia.
Lac Operon
Lac operon yog pawg ntawm cov noob muaj lub luag haujlwm rau kev thauj mus los lactose thiab cov metabolism hauv E.cov kab mob coli. Lub operon muaj ib cheeb tsam txhawb nqa thiab cov noob caj noob ces lac Z, lac Y, lac A, thiab lac I. Lub operon yog qhib los ntawm lub xub ntiag ntawm lactose. Cov lac Z, lac Y, lac A tsim beta galactosidase, lactose permease, thiab thiogalactoside transacetylase enzymes.
Permease enzyme tso cai rau lactose los rau hauv lub cell, thiab beta galactosidase hydrolyzes lactose rau qabzib thiab galactose. Transacetylase yog siv los ua haujlwm ntawm cov substrates. Yog hais tias muaj qhov zoo tshaj plaws substrate tam sim no los yog lactose tsis tuaj, lac kuv tau qhib. Qhov no tsim ib qho allolactose binding protein. Nyob rau hauv lub xub ntiag ntawm allolctose, cov repressor protein molecules khi rau allolactose molecules. Qhov no tso cai rau cov ntawv sau txuas mus ntxiv yam tsis muaj kev cuam tshuam. Thaum tsis muaj lactose, cov protein no khi rau thaj tsam txhawb nqa (tswj lub tsev) ntawm lac operon thaiv thiab nres cov noob transcription. Thaum qhov no tshwm sim tsis muaj lactose permease lossis beta galactosidase raug tsim. Yog li ntawd, lactose catabolism raug tso tseg.
Trp Operaon
Trp operon kuj yog pawg ntawm cov noob tswj los ntawm ib tus neeg txhawb nqa. Cov operon no muaj tag nrho cov noob uas xav tau rau Trp synthesis. Tryptophan feem ntau abbreviated li Trp yog ib qho txawv amino acid. Lub operon muaj trp E, trp D, trp C, trp B, thiab trp A, uas sib sau ua ke code tryptophan synthetase; enzyme uas tsim tryptophan.
Tus trp operon kuj muaj trp R uas ua rau muaj kev tawm tsam thaum xav tau. Nyob rau hauv lub xub ntiag ntawm tryptophan no operon nyob twj ywm deactivated vim hais tias tus repressor hloov nws conformation rau active daim ntawv thiab yog khi rau cov txhawb nqa cheeb tsam. Thaum tsis muaj tryptophan, cov protein repressor tau tso tawm los ntawm cheeb tsam txhawb nqa lossis yog nyob rau hauv qhov tsis ua haujlwm, uas tsis tuaj yeem khi rau thaj tsam txhawb nqa, thiab yog li kev hloov pauv ntawm cov noob yog pib ua tryptophan, vim li ntawd. Tsis zoo li lub lac operon no operon yog deactivated nyob rau hauv lub xub ntiag ntawm tryptophan, qhov no mechanism yog hu ua "tsis zoo repressive tawm tswv yim mechanism".
Qhov txawv ntawm Lac operon thiab Trp operon yog dab tsi?
• Lac operon koom nrog cov txheej txheem catabolic ntawm cov piam thaj, tab sis Trp operon koom nrog cov txheej txheem anabolic ntawm cov amino acid.
• Lac operon tau qhib thaum muaj lactose, tab sis Trp operon tau deactivated nyob rau hauv lub xub ntiag ntawm tryptophan.
• Lac operon muaj peb lub noob caj noob ces thiab lub caj dab repressor, tab sis Trp operon muaj tsib lub noob caj noob ces thiab ib tug repressor noob.
• Lac operon tsis siv "attenuation" mechanism, tab sis Trp operon siv "attenuation" mechanism.
