Lub neej yav tom ntej ntawm cov tshuaj yog tus kheej txoj kev xaiv ntawm tus kheej ntawm cov kab ke uas muaj lub luag haujlwm rau kev loj hlob thiab kev kawm ntawm ib tus kab mob. Cov chav kawm tseem ceeb ntawm cov hom phiaj kho mob nyob rau hauv cov ntaub ntawv no yog cell membrane proteins raws li lub luag hauj lwm rau muab cov teeb liab ncaj qha mus rau lub cell. Tam sim no tam sim no, yuav luag ib nrab ntawm cov tshuaj cuam tshuam rau cov cell membranes, thiab tsuas yog yuav muaj ntau dua yav tom ntej. Kab lus no tau mob siab rau kev paub txog lub luag haujlwm lom neeg ntawm daim nyias nyias.
qauv thiab kev ua haujlwm ntawm cell membrane
Los ntawm lub tsev kawm ntawv chav kawm, ntau tus nco txog cov qauv ntawm lub cev lub cev - lub cell. Ib qho chaw tshwj xeeb hauv cov qauv ntawm cov cell nyob yog ua si los ntawm plasmalemma (membrane), uas cais qhov chaw intracellular ntawm nws ib puag ncig. Yog li, nws lub luag haujlwm tseem ceeb yog tsim kom muaj kev cuam tshuam ntawm cov ntsiab lus ntawm tes thiab qhov chaw ntxiv. Tab sis qhov no tsis yog tib txoj haujlwm ntawm plasmalemma. Ntawm lwm cov kev ua haujlwm membrane ntsig txogua ntej ntawm tag nrho cov nrog membrane proteins, secrete:
- Tiv thaiv (khi antigens thiab tiv thaiv lawv nkag mus rau hauv lub cell).
- Kev thauj mus los (kom muaj kev sib pauv ntawm cov khoom nruab nrab ntawm tes thiab ib puag ncig).
- Signal (built-in receptor protein complexes muab cell irritability thiab nws cov lus teb rau ntau yam sab nraud influences).
- Zog - kev hloov pauv ntawm lub zog sib txawv: txhua yam (flagella thiab cilia), hluav taws xob (paj hlwb impulse) thiab tshuaj (synthesis ntawm adenosine triphosphoric acid molecules).
- Kev sib cuag (muab kev sib txuas lus ntawm cov hlwb siv desmosomes thiab plasmodesmata, nrog rau cov quav thiab cov kab mob ntawm cov plasmolemma).
qauv ntawm daim nyias nyias
Cov cell membrane yog ob txheej ntawm lipids. Lub bilayer yog tsim vim muaj nyob rau hauv lub lipid molecule ntawm ob qhov chaw nrog txawv zog - ib tug hydrophilic thiab ib tug hydrophobic seem. Cov txheej txheej txheej txheej ntawm daim nyias nyias yog tsim los ntawm cov polar "taub hau" nrog cov khoom siv hydrophilic, thiab hydrophobic "tails" ntawm lipids yog tig mus rau hauv lub bilayer. Ntxiv nrog rau lipids, cov qauv ntawm daim nyias nyias muaj xws li cov proteins. Xyoo 1972, American microbiologists S. D. Singer (S. Jonathan Singer) thiab G. L. Nicholson (Garth L. Nicolson) tau npaj cov kua dej-mosaic qauv ntawm cov qauv ntawm daim nyias nyias, raws li cov membrane proteins "float" nyob rau hauv lipid bilayer. Cov qauv no tau ntxiv los ntawm German biologist Kai Simons (1997) nyob rau hauv cov nqe lus ntawm kev tsim ntawm tej yam, denser cheeb tsam nrog cov proteins uas txuam nrog (lipid rafts) uas drift freely nyob rau hauv lub membrane bilayer.
Spatial qauv ntawm membrane proteins
Hauv cov hlwb sib txawv, qhov sib piv ntawm lipids thiab cov proteins sib txawv (los ntawm 25 mus rau 75% ntawm cov proteins ntawm qhov hnyav qhuav), thiab lawv nyob tsis sib xws. Los ntawm qhov chaw, cov proteins tuaj yeem yog:
- Integral (transmembrane) - ua rau hauv daim nyias nyias. Nyob rau tib lub sijhawm, lawv nkag mus rau hauv daim nyias nyias, qee zaum rov ua dua. Lawv cov cheeb tsam extracellular feem ntau nqa oligosaccharide chains, tsim glycoprotein pawg.
- Peripheral - nyob rau hauv lub hauv paus ntawm daim nyias nyias. Kev sib txuas lus nrog membrane lipids yog muab los ntawm reversible hydrogen bonds.
- Anchored - feem ntau yog nyob rau sab nraud ntawm lub xovtooj ntawm tes thiab "txheej txheem" tuav lawv rau ntawm qhov chaw yog lipid molecule raus hauv bilayer.
Kev ua haujlwm thiab lub luag haujlwm
Lub luag haujlwm lom neeg ntawm daim nyias nyias nyias muaj nyias thiab nyob ntawm lawv cov qauv thiab qhov chaw. Lawv suav nrog receptor proteins, channel proteins (ionic thiab porins), transporters, motors, thiab structural protein pawg. Txhua hom membrane protein receptors, teb rau txhua yam kev cuam tshuam, hloov lawv cov qauv spatial thiab tsim cov lus teb ntawm tes. Piv txwv li, cov tshuaj insulin tswj hwm cov piam thaj nkag mus rau hauv lub cell, thiab rhodopsin nyob rau hauv cov hlwb rhiab heev ntawm lub cev ntawm lub zeem muag ua rau muaj kev cuam tshuam ntawm qhov tshwm sim uas ua rau pom cov hlab ntsha impulse. Lub luag hauj lwm ntawm membrane protein raws yog thauj ions thiab tswj qhov sib txawv ntawm lawv cov concentrations (gradient) ntawm ib puag ncig sab hauv thiab sab nraud. Piv txwv li,sodium-potassium twj tso kua mis muab kev sib pauv ntawm cov ions sib raug zoo thiab kev thauj mus los ntawm cov khoom. Porins - los ntawm cov protein - koom nrog hauv kev hloov pauv ntawm cov dej molecules, cov neeg thauj khoom - hauv kev hloov pauv ntawm qee yam tshuaj tiv thaiv qhov concentration gradient. Hauv cov kab mob thiab protozoa, kev txav ntawm flagella yog muab los ntawm molecular protein motors. Cov txheej txheem membrane proteins txhawb cov membrane nws tus kheej thiab xyuas kom muaj kev sib cuam tshuam ntawm lwm cov plasma membrane proteins.
Cov daim nyias nyias yog qhov chaw muaj zog thiab muaj zog heev, thiab tsis yog ib qho inert matrix rau cov proteins uas nyob thiab ua haujlwm hauv nws. Nws cuam tshuam rau kev ua haujlwm ntawm daim nyias nyias ntawm cov protein, thiab lipid rafts, txav mus, tsim kev sib koom ua ke tshiab ntawm cov protein molecules. Ntau cov proteins tsuas yog tsis ua haujlwm yam tsis muaj kev koom tes, thiab lawv cov kev sib cuam tshuam intermolecular yog muab los ntawm qhov xwm txheej ntawm lipid txheej ntawm daim nyias nyias, lub koom haum ntawm cov txheej txheem uas, nyob rau hauv lem, nyob ntawm cov qauv proteins. Kev cuam tshuam hauv cov txheej txheem ntawm kev sib cuam tshuam thiab kev sib cuam tshuam ua rau muaj kev ua haujlwm tsis zoo ntawm daim nyias nyias thiab ntau yam kab mob, xws li mob ntshav qab zib mellitus thiab qog nqaij hlav malignant.
Structural organization
Cov tswv yim niaj hnub hais txog cov qauv thiab cov qauv ntawm daim nyias nyias yog raws li qhov tseeb tias nyob rau hauv daim nyias nyias peripheral feem, feem ntau ntawm lawv tsis tshua muaj ib qho, feem ntau ntawm ob peb txuam oligomerizing alpha-helices. Ntxiv mus, nws yog cov qauv no uas yog tus yuam sij rau kev ua haujlwm ntawm kev ua haujlwm. Txawm li cas los xij, nws yog kev faib cov proteins los ntawm homcov qauv tuaj yeem coj ntau yam xav tsis thoob. Ntawm ntau tshaj li ib puas tau piav qhia txog cov proteins, feem ntau kawm txog daim nyias nyias protein nyob rau hauv cov nqe lus ntawm hom oligomerization yog glycophorin A (erythrocyte protein). Rau transmembrane proteins, qhov xwm txheej zoo li nyuaj - tsuas yog ib qho protein tau piav qhia (qhov chaw photosynthetic cov tshuaj tiv thaiv kab mob - bacteriorhodopsin). Muab lub siab molecular hnyav ntawm daim nyias nyias proteins (10-240 txhiab d altons), molecular biologists muaj ib tug dav teb rau kev tshawb fawb.
Cell signaling systems
Ntawm tag nrho cov proteins ntawm cov plasma membrane, ib qho chaw tshwj xeeb belongs rau receptor proteins. Nws yog lawv uas tswj cov teeb liab nkag mus rau hauv lub xov tooj ntawm tes thiab uas tsis ua. Nyob rau hauv tag nrho cov multicellular thiab ib co kab mob, cov ntaub ntawv kis tau los ntawm tshwj xeeb molecules (cim). Ntawm cov cim qhia no yog cov tshuaj hormones (cov protein tshwj xeeb zais los ntawm cov hlwb), cov tsis muaj protein ntau, thiab ib tus neeg ions. Cov tom kawg tuaj yeem raug tso tawm thaum cov hlwb nyob sib ze raug puas tsuaj thiab ua rau muaj kev cuam tshuam ntawm kev mob tshwm sim, lub cev lub ntsiab tiv thaiv mechanism.
Lub Hom Phiaj rau Tshuaj Kho Mob
Nws yog cov kua nplaum uas yog lub hom phiaj tseem ceeb ntawm kws tshuaj, vim lawv yog cov ntsiab lus uas feem ntau cov cim tau dhau mus. "Targeting" tshuaj, ua kom nws cov kev xaiv siab - qhov no yog lub luag haujlwm tseem ceeb hauv kev tsim cov tshuaj pharmacological. Ib qho kev xaiv ntawm tsuas yog ib hom lossis txawm tias ib qho subtype ntawm cov receptor yog qhov cuam tshuam rau ib hom ntawm lub cev hlwb xwb. Xws li xaivPiv txwv li, qhov kis tau tuaj yeem paub qhov txawv ntawm cov qog nqaij hlav los ntawm qhov qub.
Tshuaj rau yav tom ntej
Cov khoom thiab cov yam ntxwv ntawm cov kua nplaum membrane twb tau siv los tsim cov tshuaj tiam tshiab. Cov thev naus laus zis no yog tsim los ntawm kev tsim cov qauv tshuaj kho mob los ntawm ntau lub molecules lossis nanoparticles "crosslinked" nrog ib leeg. Qhov "targeting" ib feem paub txog qee yam receptor proteins ntawm cov cell membrane (piv txwv li, cov cuam tshuam nrog kev loj hlob ntawm cov kab mob oncological). Rau qhov no yog ntxiv cov membrane-destroying tus neeg saib xyuas lossis blocker hauv cov txheej txheem ntawm cov protein ntau hauv cov cell. Txhim kho apoptosis (qhov kev pab cuam ntawm ib tus kheej tuag) los yog lwm yam txheej txheem ntawm cascade ntawm intracellular transformations coj mus rau qhov xav tau ntawm raug rau ib tug pharmacological neeg sawv cev. Yog li ntawd, peb muaj cov tshuaj uas muaj qhov tsawg kawg nkaus ntawm kev phiv. Thawj cov tshuaj tiv thaiv kabmob kheesxaws no twb nyob rau hauv kev sim tshuaj thiab yuav sai sai no yuav ua tau zoo heev.
Structural genomics
Kev tshawb fawb niaj hnub ntawm cov protein molecules tau nce mus rau cov ntaub ntawv thev naus laus zis. Txoj kev dav dav ntawm kev tshawb fawb - kawm thiab piav qhia txhua yam uas tuaj yeem khaws cia hauv computer databases thiab tom qab ntawd nrhiav txoj hauv kev los siv cov kev paub no - qhov no yog lub hom phiaj ntawm cov kws tshawb fawb molecular niaj hnub. Tsuas yog kaum tsib xyoos dhau los, lub ntiaj teb tib neeg genome project pib, thiab peb twb muaj ib daim ntawv qhia ua ntu zus ntawm tib neeg cov noob. Qhov thib ob qhov project, uas lub hom phiaj los txhaiscov qauv spatial ntawm tag nrho cov "cov proteins tseem ceeb" - cov qauv genomics - tseem nyob deb ntawm kev ua tiav. Cov qauv spatial tau txiav txim siab tam sim no tsuas yog rau 60,000 ntawm ntau tshaj tsib lab tib neeg cov proteins. Thiab thaum cov kws tshawb fawb tau loj hlob tsuas yog cov piglets luminous thiab cov txiv lws suav txias-resistant nrog cov noob salmon, cov txheej txheem genomics technologies tseem yog ib theem ntawm kev paub txog kev tshawb fawb, kev siv tswv yim uas yuav tsis ntev tom ntej.
