Cov khoom

Cov yam ntxwv ntawm cov teebmeem ntawm kev hloov pauv ib txhij ua ke los hloov cov kev ua haujlwm enzymatic tsis yooj yim pom tau vim tias cov teebmeem no tsis yog ib txwm ntxiv rau hauv txoj kab.Yog li ntawd, tus cwj pwm ntawm cov teebmeem ntawm kev hloov pauv ntawm cov amino acid residues uas khi lub substrate tuaj yeem ua rau muaj txiaj ntsig zoo rau kev nkag siab ntawm substrate tshwj xeeb ntawm cov enzymes.Hauv beta-glycosidase los ntawm Spodoptera frugiperda (Sfbetagly), ob qho tib si residues Q39 thiab E451 cuam tshuam nrog substrate thiab qhov no yog qhov tseem ceeb rau kev txheeb xyuas cov substrate tshwj xeeb.Ob chav mutants ntawm Sfbetagly (A451E39, S451E39 thiab S451N39) tau npaj los ntawm qhov chaw qhia mutagenesis, qhia nyob rau hauv cov kab mob thiab purified siv affinity chromatography.Cov enzymes no tau pom tias siv p-nitrophenyl beta-galactoside thiab p-nitrophenyl beta-fucoside ua substrates.Qhov sib piv k miv / Km rau ib leeg thiab ob chav mutants ntawm Sfbetagly uas muaj qhov chaw qhia kev hloov pauv ntawm txoj haujlwm Q39 thiab E451 tau siv los ua kom pom tias cov nyhuv ntawm lub zog dawb ntawm ESdouble dagger (enzyme-transition xeev complex) ntawm ob qhov kev hloov pauv (Gdouble daggerxy) tsis yog qhov suav ntawm cov teebmeem tshwm sim los ntawm kev hloov pauv ib leeg (Gdouble daggerx thiab Gdouble daggery).Qhov sib txawv ntawm Gdouble dagger qhia tias qhov cuam tshuam ntawm kev hloov pauv ib feem sib tshooj.Li no, cov nyhuv no suav tsuas yog ib zaug hauv Gdouble daggerxy.Cov ntaub ntawv crystallographic ntawm beta-glycosidases qhia pom muaj cov khoom siv hydrogen bidentate nrog cov residues Q39 thiab E451 thiab tib pawg hydroxyl ntawm substrate.Yog li ntawd, ob qho tib si thermodynamic thiab crystallographic cov ntaub ntawv qhia tias cov seem Q39 thiab E451 ua rau muaj kev cuam tshuam rau lawv cov kev cuam tshuam nrog cov substrate.