New insight into the mode of action of a GH74 xyloglucanase on tamarind seed xyloglucan: Action pattern and cleavage site
Résumé
Structural elucidation of plant cell wall xyloglucan through the analysis of enzymatically produced fragments
requires detailed knowledge of enzymes hydrolytic mechanism. In this note, the mode of action and cleavage site
of commercial recombinant xyloglucanases (GH74, Paenibacillus sp.) was studied on native and fluorescent-
tagged tamarind xyloglucan. In complement to information provided by the manufacturer, GH74 hydrolysis
was shown dual endo/exo- and exo-processive with low affinity towards labelled reducing-ends. GH74 accom-
modated X/G in its subsite --1 and X/L in its subsite +1. Moreover, hydrolysis kinetic indicated a GH74 activity
inhibition by excess products. These results will help for application of this enzyme in xyloglucans structural
analysis or for processing cell walls.