PubMed:2974758 JSONTXT

{"project":"sentences","denotations":[{"id":"TextSentencer_T1","span":{"begin":0,"end":80},"obj":"Sentence"},{"id":"TextSentencer_T2","span":{"begin":81,"end":387},"obj":"Sentence"},{"id":"TextSentencer_T3","span":{"begin":388,"end":653},"obj":"Sentence"},{"id":"TextSentencer_T4","span":{"begin":654,"end":812},"obj":"Sentence"},{"id":"TextSentencer_T5","span":{"begin":813,"end":1024},"obj":"Sentence"},{"id":"TextSentencer_T6","span":{"begin":1025,"end":1284},"obj":"Sentence"},{"id":"TextSentencer_T7","span":{"begin":1285,"end":1379},"obj":"Sentence"},{"id":"T1","span":{"begin":0,"end":80},"obj":"Sentence"},{"id":"T2","span":{"begin":81,"end":387},"obj":"Sentence"},{"id":"T3","span":{"begin":388,"end":653},"obj":"Sentence"},{"id":"T4","span":{"begin":654,"end":812},"obj":"Sentence"},{"id":"T5","span":{"begin":813,"end":1024},"obj":"Sentence"},{"id":"T6","span":{"begin":1025,"end":1284},"obj":"Sentence"},{"id":"T7","span":{"begin":1285,"end":1379},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"Recognition of oligosaccharide substrates by N-acetyl-glucosaminyltransferase-V.\nSix analogs of the trisaccharide 8-methoxycarbonyloctyl 6-O-[2-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-alpha-D-mannopyrano syl] -beta-D-mannopyranoside (3), a previously reported acceptor for N-acetylglucosaminyltransferase-V (GnT-V) have been chemically synthesized and evaluated as GnT-V acceptors. Replacement of the beta-D-man rho-O(CH2)8COOMe \"reducing end\" of 3 by beta-D-Glc rho-O(CH2)7 CH3 gave octyl 6-O-[2-O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl]-alpha-D- mannopyranosyl)-beta-D-glucopyranoside (5) whose activity was indistinguishable from that of 3. Removal of the 4-OH group of the beta-D-Glc residue in 5 had little effect on the activity, while the corresponding 4-O-methyl derivative was twice as active. Replacement of the C-6 pro-R hydrogen of the same residue by a methyl group gave the L-glycero-D-gluco derivative 8, whereas replacement of the corresponding pro-S hydrogen gave the D-glycero-D-gluco compound 9. Trisaccharide 8, whose rotameric distribution about the C-5-C-6 bond is sterically biased towards the gg conformation was less than half as active as 5 as a GnT-V acceptor, whereas 9, which is biased towards the gt conformation, was more than twice as active. These results provide evidence for the conformational control of oligosaccharide biosynthesis."}