Glycerophosphodiester phosphodiesterase domain of Streptomycin coelicolor (GlpQ1) and similar proteins
This subfamily corresponds to the glycerophosphodiester phosphodiesterase domain (GDPD) present in a group of putative bacterial and eukaryotic glycerophosphodiester phosphodiesterases (GP-GDE, EC 126.96.36.199) similar to Escherichia coli periplasmic phosphodiesterase GlpQ, as well as plant glycerophosphodiester phosphodiesterases (GP-PDEs), all of which catalyzes the Ca2+-dependent degradation of periplasmic glycerophosphodiesters to produce sn-glycerol-3-phosphate (G3P) and the corresponding alcohols. The prototypes of this family include putative secreted phosphodiesterase encoded by gene glpQ1 (SCO1565) from the pho regulon in Streptomyces coelicolor genome, and in plants, two distinct Arabidopsis thaliana genes, AT5G08030 and AT1G74210, coding putative GP-PDEs from the cell walls and vacuoles, respectively.
Comment:The catalytic mechanism of glycerophosphodiester phosphodiesterases is based on the metal ion-dependent general acid-base reaction.
Comment:Based on structure evidence and site-directed mutagenesis of Thermoanaerobacter tengcongensis glycerophosphodiester phosphodiesterase, the catalytic site consists of two conserved histidine residues which serve as general acid and general base in catalyzing the hydrolysis of the 3'-5' phosphodiester bond.