Qhov sib txawv tseem ceeb ntawm cov protein subunit thiab tus sau yog tias cov protein subunit yog ib qho sib cais polypeptide saw ntawm cov protein uas sib sau ua ke nrog lwm cov polypeptide chains los tsim cov protein complex thaum, cov protein ntau yog thaj tsam sib txuas ntawm cov saw hlau polypeptide. ntawm cov protein uas nquag folds ntawm nws tus kheej mus rau hauv ib qho compact, hauv zos, thiab ib nrab ywj siab unit.
Protein subunit thiab domain yog qhov tseem ceeb ntawm cov protein ntau ntau. Proteins yog polymers ua los ntawm polypeptides. Txhua polypeptide saw tsim los ntawm monomer hu ua amino acid. Ib tug complex protein muaj cov qauv sib txawv xws li subunits, domains, motif, thiab quav. Cov qauv txheej txheem ntawm cov protein ntau yog qhov tseem ceeb heev rau nws cov qauv thiab thaum kawg rau nws txoj haujlwm.
YPab Protein Subunit yog dab tsi?
Ib lub protein subunit yog ib qho sib cais polypeptide saw ntawm cov protein uas sib sau ua ke nrog lwm cov polypeptide chains los tsim cov protein complex. Nyob rau hauv cov txheej txheem biology, ib tug protein subunit yog ib tug tib protein molecule uas co-assembles nrog rau lwm cov protein molecules los tsim ib tug complex protein. Cov proteins uas tshwm sim ib txwm muaj muaj tsawg tsawg ntawm cov subunits, xws li hemoglobin thiab DNA polymerase. Yog li ntawd, lawv hu ua oligomeric. Lwm cov proteins muaj ntau ntawm cov subunits, yog li lawv tau piav raws li multimeric. Piv txwv li, microtubules thiab lwm yam cytoskeleton proteins yog multimeric. Cov subunits ntawm multimeric protein yuav zoo tib yam (homologous) los yog tag nrho dissimilar (heterologous).
Daim duab 01: Protein Subunit
Nyob hauv qee cov protein ntau ntau, ib lub subunit yuav yog catalytic subunit. Ntawm qhov tod tes, lwm qhov yog ib qho kev tswj hwm subunit. Kev ua haujlwm ntawm catalytic subunit yog catalysing cov tshuaj tiv thaiv enzymatic whereas, kev ua haujlwm ntawm kev tswj hwm subunit yog txhawb lossis inhibiting nws cov haujlwm. Ib qho enzyme uas muaj ob qho tib si catalytic thiab kev tswj hwm subunits thaum sib sau ua ke feem ntau hu ua holoenzyme. Piv txwv li, enzyme chav kawm I phosphoinositide 3-kinase muaj p110 catalytic subunit thiab p85 regulatory subunit. Ntxiv mus, ib qho protein yuav tsum muaj ib lub noob rau txhua lub subunit. Qhov no yog vim lub subunit yog tsim los ntawm ib tug cais polypeptide saw uas muaj ib coding noob.
Dab tsi yog Protein Domain?
A protein domain yog thaj chaw sib txuas ntawm cov saw hlau polypeptide ntawm cov protein uas nquag folds ntawm nws tus kheej mus rau hauv ib cheeb tsam, hauv zos, thiab ib nrab ywj siab. Lub npe ntawm cov protein tseem hu ua thaj tsam ntawm polypeptide saw ntawm cov protein uas nws tus kheej ruaj khov thiab folds ntawm nws tus kheej los ntawm tus so. Lawv yog cov qauv tsim thiab ua haujlwm sib txawv hauv cov protein. Feem ntau, cov thawj tswj hwm yog lub luag haujlwm rau kev ua haujlwm tshwj xeeb lossis kev sib cuam tshuam uas ua rau lub luag haujlwm tag nrho ntawm cov protein. Piv txwv li, SH3 sau yog nyob ib ncig ntawm 50 amino acids residues. Lawv tshwm sim nyob rau hauv ntau hom proteins, xws li adapter proteins, phophatidylinositol3-kinases, phospholipases, thiab myosins. Cov npe SH3 no koom nrog kev sib cuam tshuam ntawm cov protein-protein.
Daim duab 02: Protein Domains
Cov npe sib txawv ntawm qhov ntev ntawm 50 amino acids rau 250 amino acids. Qhov luv tshaj plaws, xws li zinc ntiv tes, yog ruaj khov los ntawm cov hlau ions thiab disulphide txuas hniav. Ib lub npe feem ntau tsim cov haujlwm xws li calcium-binding EF-hand domain of calmodulin. Tsis tas li ntawd, cov npe tuaj yeem hloov pauv los ntawm kev tsim cov noob caj noob ces ntawm ib qho protein mus rau lwm tus los ua cov proteins chimeric.
Dab tsi zoo sib xws ntawm Protein Subunit thiab Domain?
- Protein subunit thiab domain yog structural units ntawm multimeric protein.
- ob leeg yog tsim los ntawm cov amino acids.
- Lawv txuas nrog lo lus "polypeptide saw".
- Ntxiv mus, lawv ob qho tib si tseem ceeb heev rau kev ua haujlwm tag nrho ntawm cov protein.
Qhov txawv ntawm Protein Subunit thiab Domain yog dab tsi?
Ib lub protein subunit yog ib qho sib cais polypeptide saw ntawm cov protein uas sib sau ua ke nrog lwm cov polypeptide chains los tsim cov protein complex. Ntawm qhov tod tes, ib qho protein ntau yog thaj chaw sib txuas ntawm cov saw hlau polypeptide ntawm cov protein uas nquag folds ntawm nws tus kheej mus rau hauv ib qho kev sib cog lus, hauv zos, thiab ib nrab ywj pheej. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm protein subunit thiab domain. Tsis tas li ntawd, ib qho protein subunit yog qhov loj dua qhov muaj protein ntau.
Cov lus hauv qab no qhia txog qhov sib txawv ntawm cov protein subunit thiab domain hauv daim ntawv tabular.
Summary – Protein Subunit vs Domain
Lub tsev thaiv cov proteins yog cov amino acids. Proteins yog tsim los ntawm condensation ntawm amino acids. Protein qauv muaj qhov loj ntawm kaum mus rau ntau txhiab amino acids. Cov qauv protein yog ruaj khov los ntawm kev sib cuam tshuam tsis zoo xws li hydrogen bonds, ionic bonds, Van der Waals rog, hydrophobic bonds, thiab covalent kev sib cuam tshuam xws li disulphide bonds. Ib tug complex protein muaj cov qauv sib txawv xws li subunits, domains, motif, thiab quav. Ib qho protein subunit yog ib txoj hlua polypeptide cais ntawm cov protein uas sib sau ua ke nrog lwm cov saw hlau polypeptide los tsim cov protein ntau. Ntawm qhov tod tes, cov protein ntau yog thaj tsam ntawm polypeptide saw ntawm cov protein uas nws tus kheej ruaj khov thiab folds ntawm nws tus kheej los ntawm tus so. Yog li, qhov no yog cov ntsiab lus ntawm qhov sib txawv ntawm protein subunit thiab domain.
