Iibhondi ze-Disulfide ziyinxalenye eyimfuneko yolwakhiwo olunemigangatho emithathu yeeproteni ezininzi.Ezi bhondi zi-covalent zinokufumaneka phantse kuzo zonke iipeptides ezingaphandle kunye neemolekyuli zeprotheyini.
Ibhondi ye-disulfide yenziwa xa i-athomu yesulfure ye-cysteine yenza i-covalent bond enye kunye nesinye isiqingatha se-athomu yesulfure ye-cystine kwiindawo ezahlukeneyo kwiprotheni.Ezi zibophelelo zinceda ukuzinzisa iiprotheni, ngakumbi ezo zifihliweyo kwiiseli.
Ukuqulunqwa ngokufanelekileyo kweebhondi ze-disulfide kubandakanya iinkalo ezininzi ezifana nolawulo olufanelekileyo lwe-cysteines, ukukhuselwa kweentsalela ze-amino acid, iindlela zokususa amaqela okukhusela, kunye neendlela zokudibanisa.
Iipeptides zamiliselwa ngeebhondi ze-disulfide
Gutuo organism has a oqolileyo disulfide bond ring technology.Ukuba i-peptide iqulethe iperi enye kuphela yeCys, ukubunjwa kwebhondi ye-disulfide kuqondile.Iipeptides zenziwe ngezigaba eziqinileyo okanye ezingamanzi,
Emva koko i-oxidized kwisisombululo se-pH8-9.I-synthesis inzima xa izibini ezimbini okanye ngaphezulu ze-disulfide bonds kufuneka zenziwe.Nangona ulwakhiwo lwebhondi ye-disulfide ludla ngokugqityezelwa emva kwexesha kwisikimu sokwenziwa, ngamanye amaxesha ukwaziswa kwe-disulfides esele yenziwe ngaphambili kunenzuzo yokudibanisa okanye yokwandisa amatyathanga e-peptide.I-Bzl liqela elikhuselayo le-Cys, i-Meb, i-Mob, i-tBu, i-Trt, i-Tmob, i-TMTr, i-Acm, i-Npys, njl., isetyenziswa ngokubanzi kwi-symbiont.Sisebenza ngokukhethekileyo kwi-disulphide peptide synthesis kuquka:
1. Izibini ezimbini zeebhondi ze-disulfide zenziwe ngaphakathi kwimolekyuli kwaye izibini ezimbini ze-disulfide bonds zenziwe phakathi kweeamolekyuli.
2. Izibini ezintathu zeebhondi ze-disulfide zenziwe ngaphakathi kwimolekyuli kwaye izibini ezintathu ze-disulfide bonds zenziwe phakathi kweemolekyuli.
3. I-insulin ye-polypeptide synthesis, apho izibini ezimbini ze-disulfide bonds zenziwe phakathi kokulandelelana kweepeptide ezahlukeneyo.
4. Ukwenziwa kweeperi ezintathu ze-disulfide-bonded peptides
Kutheni le nto iqela le-cysteineyl amino (Cys) likhethekile?
Ikhonkco lecala leCys lineqela elisebenzayo elisebenzayo.Iiathom zehydrogen kweli qela zitshintshwa ngokulula ziiradicals zasimahla kunye namanye amaqela, kwaye ngaloo ndlela zinokubumba amaqhina ahlangeneyo kunye nezinye iimolekyuli.
Iibhondi ze-Disulfide ziyinxalenye ebalulekileyo yesakhiwo se-3D yeeprotheni ezininzi.Iibhondi zebhulorho zeDisulphide zinokunciphisa ukuqina kwepeptide, ukwandisa ukuqina, kunye nokunciphisa inani lemifanekiso enokubakho.Lo mda wemifanekiso ubalulekile kumsebenzi webhayoloji kunye nozinzo lwesakhiwo.Ukutshintshwa kwayo kunokuba yinto emangalisayo kwisakhiwo sonke seprotheni.I-Hydrophobic amino acids ezifana ne-Dew, Ile, Val ziyi-helix stabilizer.Ngenxa yokuba izinzile i-disulfide-bond α-helix yokwakheka kwe-cysteine nokuba i-cysteine ayifaki iibhondi ze-disulfide.Okokuthi, ukuba zonke iintsalela ze-cysteine zibe zikwisimo esincitshisiweyo, (-SH, ethwele amaqela e-sulfhydryl yamahhala), ipesenti ephezulu yeengqungquthela ze-helical iya kwenzeka.
Iibhondi ze-disulfide ezenziwe yi-cysteine zihlala zizinzileyo kwisakhiwo semfundo ephakamileyo.Kwiimeko ezininzi, iiBridges ze-SS phakathi kweebhondi ziyimfuneko ekubunjweni kwezakhiwo ze-quaternary.Ngamanye amaxesha iintsalela ze-cysteine ezenza iibhondi ze-disulfide zihluke kakhulu kwisakhiwo sokuqala.I-topology yeebhondi ze-disulfide sisiseko sohlalutyo lweprotein yokuqala yesakhiwo se-homology.Iintsalela ze-cysteine ze-homologous proteins zigcinwe kakhulu.Kuphela i-tryptophan yayilondolozwe ngakumbi ngokwezibalo kune-cysteine.
I-cysteine ifumaneka kumbindi wendawo ye-catalytic ye-thiolase.I-cysteine inokwenza i-acyl intermediates ngokuthe ngqo kunye ne-substrate.Ifomu encitshisiweyo isebenza njenge "sulfur buffer" egcina i-cysteine kwiprotheni kwimeko encitshisiweyo.Xa i-pH iphantsi, i-equilibrium ithanda ukuncitshiswa kwe-SH ifom, kanti kwiindawo ze-alkaline -SH ilungele ukuba i-oxidized ibe yi-SR, kunye ne-R nantoni na ngaphandle kwe-athomu ye-hydrogen.
I-cysteine inokuthi isebenze kunye ne-hydrogen peroxide kunye ne-organic peroxides njenge-detoxicant.
Ixesha lokuposa: May-19-2023