Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(C))
Date (from‐to) : 2011 -2013
Author : Megumi ISHIMARU
In tomato fruit, beta-galactosidase 4 (TBG4) is an enzyme responsible for fruit softening through the degradation of beta-(1,4)-galactan in the pericarp cell wall. To gain structural insight into the substrate specificity, we determined the crystal structures of TBG4 and its complex with beta-D-galactose. TBG4 was composed of a catalytic TIM barrel domain followed by three beta-sandwich domains. This structure is similar to other beta-galactosidase belong to GH35 families.In addition, we determined the enzymatic properties and substrate specificities of TBG1. TBG4 has substrate recognition to beta-(1,4)-linkage, however, TBG1 has beta-(1,3) and beta-(1,6)-likage substrate.In these results, TBG's act on the tomato cell wall during fruits development and maturation, and seberal stage of tomato fruits cell walls construct/reconstruct to some components sugar as a substrate against TBG's.