Lub yam ntxwv koom haum ntawm lub protein molecule theem: theem nrab qauv ntawm ib tug protein

Lub hauv paus ntawm cov qauv ntawm cov nqaijrog thiab proteids ntawm lub polypeptide saw, thiab cov protein molecule yuav muaj xws li ib tug, ob tug los yog ntau tshaj circuits. Cuaj kaum, lub cev, lom thiab tshuaj thaj chaw ntawm biopolymers yog tshwm sim los tsis tau tsuas yog ib tug general tshuaj qauv uas tej zaum yuav yog ib tug "meaningless", tab sis kuj los ntawm lwm theem ntawm lub koom haum ntawm lub protein molecules.

Lub hom qauv ntawm ib tug protein yog txiav txim los ntawm qhov zoo thiab ntau amino acid muaj pes tsawg leeg. Peptide bonds yog lub hauv paus ntawm cov thawj qauv. Rau cov thawj lub sij hawm no hypothesis pom tias nyob rau hauv 1888 A. Ya. Danilevsky, thiab tom qab ntawd nws suspicions tau paub tseeb hais tias los ntawm lub synthesis ntawm peptides uas yog nqa tawm los ntawm E. Fischer. Tus qauv ntawm cov protein molecules nyob rau hauv kom meej soj ntsuam A. Ya. Danilevskim thiab E. Fischer. Raws li no ziag no, lub protein molecules muaj ib tug loj tus naj npawb ntawm cov amino acid residues uas yog kev cob cog rua ntawm peptide bonds. protein molecule zaum yuav muaj ib los yog ntau tshaj polypeptide chains.

Thaum cov thawj lug ntawm cov nqaijrog siv rau lub xeem tshuaj cov neeg ua hauj thiab proteolytic enzymes. Yog li, siv cov qauv ntawm cov Edman yog heev yooj yim kom paub tias cov davhlau ya nyob twg amino acids.

Cov theem nrab qauv ntawm cov protein qhia tau hais tias ib tug spatial configuration ntawm cov protein molecule. Muaj cov nram qab no theem nrab qauv hom: alpha-helix, beta-kauv, collagen helix. Zaum tau pom hais tias tus feem ntau cov yam ntxwv ntawm cov alpha-helix qauv ntawm cov peptides.

Cov theem nrab qauv ntawm cov protein yog stabilized los ntawm txhais tau tias ntawm hydrogen bonds. Cov yav tas tshwm sim nruab nrab ntawm cov hydrogen atoms sib raug zoo rau ib tug electronegative nitrogen atom ntawm ib tug peptide daim ntawv cog lus, thiab ib tug carbonyl oxygen atom ntawm plaub ib qho ntawm nws cov amino acids, thiab lawv qhia raws kauv. Zog suav qhia tau hais tias lub polymerization ntawm cov amino acids yog ntau npaum txoj kev alpha-helix, uas yog tam sim no nyob rau hauv cov haiv neeg proteins.

Cov theem nrab qauv ntawm ib tug protein: beta-daim ntawv qauv

Polypeptide chains nyob rau hauv beta-folds tag nrho kev ncua. Beta-folds yog tsim los ntawm kev sis raug zoo ntawm ob peptide bonds. Qhov no qauv yog cov yam ntxwv fibrous cov nqaijrog (keratin, fibroin, etc.). Nyob rau hauv kev, beta-keratin yus muaj los ntawm ib tug thaum uas tig mus uake ntawm polypeptide chains uas ntxiv stabilized los ntawm interchain disulfide bonds. Txhob lo lo ntxhuav fibroin ze polypeptide chains yog antiparallel.

Cov theem nrab qauv ntawm cov protein: collagen helix

Cov tsim muaj peb spiralized tropocollagen chains, uas muaj ib tug pas nrig zoo. Spiralized saw curl thiab tsim ib tug superhelix. Helix stabilized los ntawm hydrogen bonds ntawm lub hydrogen ntawm lub peptide tshwm sim amino acid amino residue nyob rau hauv ib tug saw thiab cov pa ntawm cov carbonyl pab pawg neeg ntawm cov amino acid residue ntawm lwm saw. Nthuav collagen qauv muab siab zog thiab elasticity.

Lub tertiary qauv ntawm cov protein

Feem ntau cov nqaijrog nyob rau hauv cov neeg lub xeev yog heev compact qauv, uas yog txiav txim los ntawm tus duab, loj, me, thiab polarity ntawm cov amino acid radicals, thiab cov amino acid ib theem zuj zus.

Ib tug tseem ceeb cawv rau cov tsim ntawm haiv neeg protein conformation, los yog ib tug tertiary lug muaj hydrophobic thiab ionic kev sib tshuam, hydrogen bonds, thiab lwm yam .. Nyob rau hauv qhov kev txiav txim ntawm cov rog no tiav thermodynamically tsim nyog conformation ntawm cov protein molecule thiab nws cov stabilization.

Lub quaternary qauv

Qhov no zoo ntawm cov qauv ntawm cov molecule yog lub txiaj ntsim ntawm kev koom ntawm ob peb subunits rau hauv ib molecule complex. Muaj pes tsawg leeg ntawm txhua subunit muaj xws li cov thawj, nrab thiab tertiary lug.