Cov khoom

Mechanistic insights rau hauv Ca2 + - nyob ntawm tsev neeg ntawm alpha-mannosidases hauv tib neeg lub plab symbiont.

Cov kab mob colonic, piv txwv los ntawm Bacteroides thetaiotaomicron, ua lub luag haujlwm tseem ceeb hauv kev saib xyuas tib neeg kev noj qab haus huv los ntawm kev siv cov tsev neeg loj ntawm glycoside hydrolases (GHs) los siv cov khoom noj khoom haus polysaccharides thiab host glycans ua cov as-ham.Xws li GH tsev neeg nthuav dav yog ua piv txwv los ntawm 23 tsev neeg GH92 glycosidases encoded los ntawm B. thetaiotaomicron genome.Ntawm no peb qhia tau hais tias cov no yog alpha-mannosidases uas ua los ntawm ib qho kev txav chaw los siv tus tswv N-glycans.Cov qauv peb-dimensional ntawm ob GH92 mannosidases txhais ib tsev neeg ntawm ob lub npe proteins uas lub chaw catalytic nyob ntawm qhov chaw sib txuas, muab cov kua qaub (glutamate) thiab lub hauv paus (aspartate) kev pab rau hydrolysis hauv Ca(2+)- kev vam meej.Cov qauv peb-dimensional ntawm GH92s nyob rau hauv complex nrog inhibitors muab kev nkag siab rau qhov tshwj xeeb, mechanism thiab conformational itinerary ntawm catalysis.Ca(2+) plays lub luag haujlwm tseem ceeb hauv kev pab cuam tshuam cov mannoside kom deb ntawm nws hauv av-xeev (4)C(1) lub rooj zaum hloov mus rau lub xeev hloov pauv.(Bibliography: Nat.Chem.Biol.6, 125-32, (2010)

Frontal affinity chromatography ntawm ovalbumin glycoasparagines ntawm concanavalin A-sepharose kab.Ib qho kev tshawb fawb ntau ntawm kev sib khi tshwj xeeb ntawm lectin.

Kev sib cuam tshuam ntawm Sepharose 4B-immobilized concanavalin A (ConA) nrog 10 glycoasparagines tau los ntawm ovalbumin tau tshawb xyuas ntau los ntawm frontal affinity chromatography.Nyob rau hauv txoj kev no, cov tshuaj carbohydrate yog siv tas li mus rau ConA-Sepharose kem thiab qhov retardation ntawm elution pem hauv ntej yog ntsuas raws li qhov ntsuas ntawm lub zog ntawm kev sib cuam tshuam.Lub dissociation tas li (Kd) rau txhua saccharide nrog ConA tuaj yeem txiav txim siab.Kev soj ntsuam ntawm kev khi ntawm p-nitrophenyl-alpha, D-mannoside tau pom tias cov khoom sib khi ntawm ConA tsis hloov qhov tseem ceeb tom qab immobilization ntawm Sepharose 4B.Txhua ntawm ovalbumin glycoasparagines tau sau npe nrog tritium los ntawm kev txo qis methylation rau kev tshuaj xyuas.Ib qho kev sib piv ntawm Kd qhov tseem ceeb tau pom tias kev khi ntawm ConA sib txawv nrog cov qauv sib txawv me ntsis ntawm cov saw glycosyl.Cov txiaj ntsig tau qhia tias ConA lees paub qhov tshwj xeeb glycosyl saw qauv, Txiv neej alpha 1-6 (Txiv neej alpha 1-3) Txiv neej, uas tsawg kawg ib pawg hydroxyl ntawm C-3 txoj hauj lwm ntawm C-6-txuas mannose yuav tsum dawb.