Umbutho noshowo amanqanaba kwimolekyule yeprotheni: Isakhiwo sesekondari protini

Isiseko ubume iiprothini kunye proteids chain polypeptide, kwaye kwimolekyule yeprotheni kusenokuquka iziphaluka elinye, amabini okanye nangaphezulu. Nakuba kunjalo, iimpawu zomzimba, ngokwendalo kunye lwemichiza biopolymers zibangelwa kuphela isakhiwo imichiza ngokubanzi elinokuba yi "nantsingiselo", kodwa ngamanye amanqanaba nokucwangciswa iimolekyuli protein.

Isakhiwo ephambili iproteni kuxhomekeke ubunjani kunye neenkcukacha zamanani acid acid kuqamba. iibhondi Peptide asisiseko isakhiwo zaseprayimari. Kuba okokuqala le hypothesis wacebisa ngo-1888 A. Ya. Danilevsky, yaye kamva wakhala zakhe malingqinwe Yindibanisela peptides oluqhutywa yi E. Fischer. Ubume molecule iiprothini iinkcukacha kuphandwe A. Ya. Danilevskim kunye E. Fischer. Ngokwalo mbono, ezo molekyuli protein kuquka inani elikhulu zeentsalela acid acid abaqhagamshelwe ngeentambo peptide. protein molecule abe omnye okanye ngaphezulu imixokelelwane polypeptide.

Xa izakhiwo eziphambili kwiiproteni asetyenziselwa arhente test iikhemikhali kunye nee-enzayim proteolytic. Ngenxa yoko, usebenzisa indlela Edman Kulula kakhulu ukuba ukuchonga asidi terminal acid.

Isakhiwo yesibini kwiproteni ubonisa loqwalaselo lwendawo kwemolekyuli protini. Kukho iintlobo isakhiwo zilandelayo aphakamileyo: Alpha-kweleli, beta-ephotheneyo, collagen Helix. Izazinzulu ziye zafumanisa ukuba eyona uphawu ubume alpha-kweleli le peptides.

Isakhiwo yesibini kwiproteni leyo izinze esebenzisa iintambo hydrogen. phakathi kuvela nevuthisayo athom hydrogen yesondo i nitrogen atom electronegative omnye peptide iqhina, kunye atom carbonyl oksijini omnye sesine asidi zayo acid, yaye wayalela ecaleni isantya. izibalo Energy zibonisa ukuba polymerization kwezi acid kakhulu kakuhle ekunene alpha-kweleli, nto leyo ekhona iiproteni zomthonyama.

Isakhiwo sesekondari protini: isakhiwo beta-sheet

amatyathanga Polypeptide Beta-nezibaya ziyanatyiswa ngokupheleleyo. Beta-ezibayeni akhiwa impefumlelwano iintambo ezimbini peptide. Esi sakhiwo iimpawu iiproteni ezinezikhondo (zenziwe ngekeratini, fibroin, njalo njalo). Ngokukodwa, beta-ngekeratini iphawulwa amalungiselelo engumzekelo imixokelelwane polypeptide ukuba ngcono ngakumbi interchain iibhondi disulfide. Iintsontelo polypeptide isilika fibroin elingummelwane ezi antiparallel.

Isakhiwo yesibini kwiproteni: Helix collagen

Ukwenziwa iqulathe xo tropocollagen spiralized ezintathu, nto leyo iba imilo ngentonga. Spiralized chain kweziphothe ibe superhelix. Helix yazinza ngeentambo hydrogen phakathi hydrogen le peptide ziyenzeka acid acid acid kwintsalela sisonke elinye kunye oksijini iqela carbonyl i eseleyo acid acid enye chain. Thaca isakhiwo collagen unika amandla aphezulu kunye luthambe.

Isakhiwo neliphezulu protini

neeproteni Uninzi zikarhulumente eziyinzalelwane isakhiwo compact kakhulu, nto leyo umiselwa imilo, ubukhulu, nokuba wokwephuka le radicals acid acid, kunye nolandelelwano acid acid.

A nempembelelo ebalulekileyo ukuyilwa zomthonyama protein Ukumila, okanye izakhiwo ephakamileyo kufuneka unxibelelwano hydrophobic kwaye ionic, iibhondi hydrogen, njl .. Ngaphantsi isenzo kwezi imikhosi iyazalisekiswa Ukumila thermodynamically kufanelekile kwemolekyuli protein nokuzinziswa yayo.

Isakhiwo koqeqesho

Olu hlobo isakhiwo molecule ngenxa yokunxulumana subunits eziliqela imbaxa molecule elilodwa. Ukubunjwa enganeno ngamnye kuquka izakhiwo lokuqala, lesibini nelesithathu.