Fig. 6
F1-ORF13 sulfatase activity on N-glycans. A F1-ORF13 sulfatase substrate specificity. F1-ORF13 was assayed on different APTS-labelled N-glycan substrates generated from human immunoglobulin. Substrate and product were monitored by xCGE-LIF. Structure assignment was enabled by comparing the normalized migration times with those of a N-glycan database and confirmed by exoglycosidase digests (Cajic S, Hennig R, Grote V, Reichl U and Rapp E; manuscript in preparation). B F1-ORF13 optimal pH. Optimal pH for F1-ORF13 was determined using APTS-labelled FA2G0-SO4, following product formation by xCGE-LIF. C F1-ORF13 ion requirement. Activity of F1-ORF13 was assayed in the presence of different metal ions. Formation of the reaction product was monitored by xCGE-LIF. The x-axis (time) of the electropherograms was normalized to two internal standards by glyXtoolCE, resulting in double normalized migration time units (MTU”). Signal Intensities were normalized to the total peak height, resulting in relative peak height proportions (%). Peaks marked with (*) correspond to the internal standard used for migration time normalization in xCGE-LIF. Glycans are represented using the SNFG nomenclature [69]