细胞与分子生物学3

ThePlantCellWallPart1•Cellwallstructure•PolysaccharidesinthewallPart2•CellwallbiosynthesisPart3•Cellwallproteins•Aromaticcompounds(incl.lignin)•Cross-linking•Cellexpansion•CellwalldegradationTheGolgiapparatusisa‘sugarfactory’Arabidopsisthaliana≈500glycosyltransferasesinArabidopsis150differentglycosyltransferase(GTs)activitiesrequired?•methyltransferases•acetyltransferases•feruloyltransferases•NDP-sugartransporters•NDP-sugarinterconvertingenzymes•hydrolasesNucleotidesugarsarethesubstratesforpolysaccharidebiosynthesisUDP-sugarsGDP-sugars(ADP-glucoseisprecursorforstarchbiosynthesis)NucleotidesugarsarethesubstratesforpolysaccharidebiosynthesisUDP-sugarsGDP-sugars(ADP-glucoseisprecursorforstarchbiosynthesis)ß-glucansynthasesareexamplesofinvertingglycosyltransferasesOOHOHOHOUDPCOOHOOOHOHORCOOHOOHOHOHCOOH-UDP-D-Galacturonicacid-1,4-Galacturonan(n)OOHOHOHOCOOHOOOHOHORCOOHOOHOHCOOH-1,4-Galacturonan(n+1)+-galacturonansynthasesareexamplesofretainingglycosyltransferases-UDP-D-Glucose-1,4-Glucan(n)+-1,4-Glucan(n+1)OCH2OHOHOHOROCH2OHOHOHOHOOCH2OHOHOHOROCH2OHOOHOHOOCH2OHOHOHOHOCH2OHOHOHOHOUDP