@article { ISI:000231492800012,
	title = {Enzymatic properties of native and deglycosylated hybrid aspen (Populus tremula x tremuloides) xyloglucan endotransglycosylase 16A expressed in Pichia pastoris},
	journal = {BIOCHEMICAL JOURNAL},
	volume = {390},
	number = {1},
	year = {2005},
	month = {AUG 15},
	pages = {105-113},
	type = {Article},
	abstract = {The cDNA encoding a xyloglucan endotransglycosylase, PttXET16A, from hybrid aspen (Populus tremula x tremuloides) has been isolated from an expressed sequence tag library and expressed in the methylotrophic yeast Pichia pastoris. Sequence analysis indicated a high degree of similarity with other proteins in the XTH (xyloglucan transglycosylase/hydrolase) gene subfamily of GH16 (glycoside hydrolase family 16). In addition to the conserved GH16 catalytic sequence motif, PttXET16A contains a conserved N-glycosylation site situated proximal to the predicted catalytic residues. MS analysis indicated that the recombinant PttXET16A expressed in P. pastoris is heterogeneous due to the presence of variable N-glycosylation and incomplete cleavage of the a-factor secretion signal peptide. Removal of the N-glycan by endoglycosidase H treatment did not influence the catalytic activity significantly. Similarly, site-directed mutagenesis of Asn(93) to serine to remove the N-glycosylation site resulted in an enzyme which was comparable with the wild-type enzyme in specific activity and thermal stability but had clearly reduced solubility. Hydrolytic activity was detected neither in wild-type PttXET16A before or after enzymatic deglycosylation nor in PttXET16A N93S (Asn(93) -> Ser) mutant.},
	issn = {0264-6021},
	doi = {10.1042/BJ20041749},
	author = {Kallas, AM and Piens, K and Denman, SE and Henriksson, H and Faldt, J and Johansson, P and Brumer, H and Teeri, TT}
}
