1.1 α-Helices. Lub α-helix yog ib qho tseem ceeb ntawm cov qauv protein thib ob, tsim thaum cov amino acids "cua" los tsim ib txoj cai-tes helix qhov twg sab-chains taw tes tawm ntawm lub hauv paus kauj(Fig. 3.1A, B).
Dab tsi ua rau alpha helices tsim?
Lub alpha helix yog tus cwj pwm los ntawm txoj cai nruj nreem nyob rau hauv cov amino acid saw uas ua rau nws tsim ib tug pas nrig. Hydrogen bonds ntawm hydrogen hauv ib pawg amino thiab cov pa oxygen hauv pawg carboxyl ntawm cov amino acid ua rau cov qauv no.
alpha helices thiab beta nplooj ntawv ua li cas?
Lub alpha helix yog tsim thaum lub polypeptide chains twist mus rau hauv ib tug kauv Qhov no tso cai rau tag nrho cov amino acids nyob rau hauv cov saw los tsim hydrogen bonds ib leeg.… Daim ntawv beta pleated yog polypeptide chains khiav ntawm ib sab. Nws hu ua daim ntawv pleated vim yog nthwv dej zoo li lub ntsej muag.
Dab tsi amino acids tsim helices?
Cov amino-acid sib txawv muaj qhov sib txawv rau kev tsim α-helical qauv. Methionine, alanine, leucine, glutamate, thiab lysine uncharged("MALEK" nyob rau hauv cov amino-acid 1-ntawv cov lej) txhua tus muaj qhov tshwj xeeb tshaj plaws-kev ua kom muaj zog, thaum proline thiab glycine tsis zoo. helix-forming propensities.
Yuav ua li cas cov qauv protein thib ob yog tsim los ntawm cov qauv thawj?
Ib tus qauv ntawm cov protein tsuas yog txhais los ntawm nws cov amino acid ib ntus, thiab yog tsim los ntawm peptide bonds ntawm cov amino acid residues uas nyob ib sab. Cov qauv thib ob tshwm sim los ntawm hydrogen bonding raws polypeptide qaum, ua rau alpha-helices thiab beta-pleated nplooj.
